which was to be demonstrated

prove; demonstrate; give a proof

доказвам истинността на/ доказвам напълно demonstrate the truth of; substantiate

доказвам твърдение make/prove a point, prove an assertion/a contention

доказвам, че някое твърдение е вярно prove a statement true

доказвам, че съм прав make out o.'s case

доказвам на дело prove in practice/deed

доказвам неоснователността на belie, give the lie to

доказвам алиби establish an alibi

което и трябваше да се докаже which was to be demonstrated, мат. Q.E.D.

искам да докажа argue (че that)

доказвам, че съм... prove o.s. to be...

* * *

дока̀звам,

гл. prove; demonstrate; give a proof; \доказвам алиби establish an alibi; \доказвам истинността на/\доказвам напълно demonstrate the truth of; substantiate; \доказвам на дело prove in practice/deed; \доказвам неоснователността на belie, give the lie to; \доказвам нечия вина prove/establish s.o.’s guilt; \доказвам твърдение make/prove a point, prove an assertion/a contention; \доказвам, че някое твърдение е вярно prove a statement true; \доказвам, че съм … prove o.s. to be …; \доказвам, че съм прав make out o.’s case; искам да докажа argue (че that); което и трябваше да се докаже which was to be demonstrated, мат. Q.E.D.

* * *

argue: to доказвам the truth of - доказвам истинността на; establish ; еvidence ; make out ; manifest: to доказвам an assertion; reason ; sustain ; vindicate

* * *

1) Латинский язык: Quod Erat Demonstrandum

2) Военный термин: Quality Evaluation Division

3) Техника: quick erection dome, which was to be proved

4) Шутливое выражение: Queen Elizabeth Dearie, Quick Easy Dirty

5) Математика: что и требовалось доказать (quod erat demonstrandum)

6) Оптика: quantum electrodynamics

7) Сокращение: Quality, Efficiency, Dependability, Quod Erat Demonstrandum (which was to be demonstrated)

8) Университет: Quite Easily Done

9) Электроника: Quantum Electro Dynamics

10) Вычислительная техника: Quod Erat Demonstrandum (which was to be demonstrated, Latin)

11) Транспорт: Shall I follow the pilot vehicle?

12) Фирменный знак: Quality Electricals Direct, Queen Elizabeth Distribution

13) Образование: Quality Education Drive

14) Макаров: квантовая электродинамика

15) Расширение файла: Quick Text Editor

1) Latin: QED

2) Abbreviation: QED (which was to be demonstrated)

3) Information technology: QED (which was to be demonstrated, Latin)

1) Latin: QED

2) Abbreviation: QED (which was to be demonstrated)

3) Information technology: QED (which was to be demonstrated, Latin)

* * *

дока̀жа,

дока̀звам гл. prove; demonstrate; give a proof; \докажа алиби establish an alibi; \докажа истинността на/\докажа напълно demonstrate the truth of; substantiate; \докажа на дело prove in practice/deed; \докажа неоснователността на belie, give the lie to; \докажа нечия вина prove/establish s.o.’s guilt; \докажа твърдение make/prove a point, prove an assertion/a contention; \докажа, че някое твърдение е вярно prove a statement true; \докажа, че съм … prove o.s. to be …; \докажа, че съм прав make out o.’s case; искам да докажа argue (че that); което и трябваше да се докаже which was to be demonstrated, мат. Q.E.D.

* * *

(abbr. quod erat demonstrandum) come dovevasi dimostrare (qed, c.d.d.)

* * *

sigla

1 (lat.: quod erat demonstrandum) ( which was to be demonstrated) come dovevasi dimostrare (c.d.d.)

2 (fis., quantum electrodynamics) elettrodinamica quantistica.

* * *

(abbr. quod erat demonstrandum) come dovevasi dimostrare (qed, c.d.d.)

• (QED)

• Which was to be demonstrated

1 piece of evidence.

no tengo pruebas I have no proof o evidence

2 sign.

en o como prueba de in o as proof of

3 test.

de prueba on approval (producto comprado)

prueba de alcoholemia breath test

prueba del embarazo pregnancy test

la prueba de fuego the acid test

prueba de resistencia endurance test

4 test.

prueba de acceso entrance examination

prueba de aptitud aptitude test

5 ordeal, trial (trance).

6 event (sport).

prueba de saltos show jumping (de equitación)

7 proof (Imprenta).

8 sample.

9 audition.

3^rd person singular (él/ella/ello) present indicative of spanish verb: probar.

2^nd person singular (tú) Imperative of Spanish verb: probar.

* * *

► nombre femenino

1 (demostración) proof

■ ahí está la prueba de que no decía la verdad there's the proof that he wasn't telling the truth

2 (experimento) experiment, trial

■ hemos hecho la prueba de no regañarla a ver qué pasa we've tried not telling her off to see what happens

■ haz la prueba try it

3 (examen) test

4 TÉCNICA trial

5 MEDICINA test

6 DEPORTE event

7 DERECHO evidence

■ lo absolvieron por falta de pruebas he was acquitted due to lack of evidence

8 (en imprenta) proof

■ necesitamos un corrector de pruebas we need a proofreader

9 (en costura) fitting

\

a prueba de proof against

■ a prueba de balas bulletproof

■ a prueba de golpes shockproof

en prueba de as a sign of

■ toma este anillo en prueba de mi amor take this ring as a sign of my love

poner a prueba to put to the test

prueba de acceso entrance examination

prueba de fuego acid test

prueba del embarazo pregnancy test

prueba nuclear nuclear test

* * *

1) proof

2) evidence

3) event

4) test, trial

5) token

* * *

1) (=demostración) proof

2) (Jur) piece of evidence

3) (=examen) (Escol, Univ, Med) test; [de actor] (Cine) screen test; (Teat) audition

- ser la prueba de fuego de algo

4) (=ensayo)

a) [gen]

b)

c)

5) (Dep) (=disciplina) event; (=carrera) race

6) (Cos) fitting

7) (Fot) print

8) [de comida] (=acto) testing, sampling; (=cantidad) taste, sample

9) LAm [en el circo] (=número) circus act; And (=función) circus show, performance

10) pl pruebas (Tip) proofs

* * *

1)

a) (demostración, testimonio) proof

b) (Der) piece of evidence

- prueba de compra

- pruebas materiales

2) (Educ) test; (Cin) screen test, audition; (Teatr) audition

- prueba de aptitud

- prueba de fuego

3)

a) (ensayo, experimento)

b) ( circunstancia difícil)

c) (en locs)

d) ( en costura) fitting

- prueba de laboratorio

- prueba del alcohol or de la alcoholemia

- prueba del embarazo

- prueba nuclear

4) (Fot, Impr) proof

5) (Dep)

pruebas, etc see probar

* * *

= assaying, edit sheet, engraving, field trial, galley, page proof, proof slip, proofsheet, proving trial, trial, trial print, trial run, tangible evidence, reassurance, test, proof copy, proof, galley proof, proof sheet, lab test, test session, test drive, test run, modelling exercise, performance test, ordeal, audition, tryout.

Ex. Suppose you have classified, by UDC, the document 'Select methods of metallurgical assaying', class number 669.9.

Ex. To print MARC record edit sheets, press 'Alt F3', which means to press and hold down the 'Alt' key, followed by pressing the 'F3' key.

Ex. An art print is an engraving, etching, lithograph, etc. printed from the plate prepared by the artist.

Ex. Telidon was first demonstrated in 1978, and small-scale field trials videotex and teletext started in 1980.

Ex. Final editing and corrections are done on this terminal, and galleys are sent to the customer.

Ex. Catalogue cards are available for each item recorded in the weekly BNB, and for Cataloguing-in-Publication (CIP) records prepared from the page proofs of forthcoming titles.

Ex. Since it seems clear that many libraries will not be automating, they will have to depend on traditional sources of cataloging data such as cards, proof slips, and book catalogs.

Ex. Alternatively a library may receive proofsheets of every LC catalogue record, and make a selection from these when items arrive.

Ex. Bureaux can be useful for proving trials, and the deferment of commitments until a suitable size of data base has been accumulated in the computer system.

Ex. The intention was to determine which department within each library has the responsibility for arranging trials of products.

Ex. Trial prints (proofs) of the formes were then made, and compared with the copy from which they had been set.

Ex. This course can be taken by librarians as well as readers and its trial run started in 1987.

Ex. The chairwoman of the board had decided that as part of the screening process those who had successfully survived the initial winnowing should furnish the board with tangible evidence of how they might perform on a specific assignment.

Ex. Such reassurance becomes particularly important if the inquirer has not sampled the file, either in a printed format or in browsing online.

Ex. The suppliers claim that tests show this to be sufficient for 980 of all entries.

Ex. One can only point to the efforts being made at BNB to produce cataloguing records as quickly as possible from proof copies if at all feasible.

Ex. The catalogue has been automated since 1984, and further proof of the library's value and ability to move with the times are shown by its 8,400 plus individual members.

Ex. Checking is carried out by comparison of the galley proof against the manuscript.

Ex. These have the advantages of economy, and (if the subscriber desires) selectivity because the records on the proof sheets are divided into broad categories which can be obtained separately.

Ex. The article 'Search engine showdown' reports the results of lab tests carried out on 7 major World Wide Web (WWW) search engines available free of charge on the Internet.

Ex. A cognitive walkthrough consists of a re-enactment of a test session in which the user is queried about their movements and decisions throughout the test session.

Ex. The author presents an evaluation of PatentView in terms of product information, search and retrieval facilities, documentation, and test drive.

Ex. Test run results show that by taking advantage of the favourable properties of holography shorter response times are obtained.

Ex. The modelling exercise would indicate which model was most economic and which was most cost-effective.

Ex. The domains covered in the performance tests for the area of cosmetology were: hair cut, permanent wave, shampooing, wigs and hairpieces, skin care, hair conditioners (scalp and treatment), and manicuring.

Ex. The article has the title ' Ordeals of a frustrated European intermediary with competitive intelligence searching'.

Ex. Applicants may receive information regarding these auditions by sending a one-page written resume to this office no later than October 20, 2008.

Ex. Nearly 200 players submitted applications to be considered for the tryouts and the pool was narrowed to 84.

----

* anterior a la prueba = pretrial.

* antes de la prueba = pretest [pre-test].

* a prueba = on trial.

* a prueba de bombas = ruggedised [ruggedized, -USA], bomb-proof.

* a prueba de conejos = rabbit-proof.

* a prueba de fallos = fail-safe.

* a prueba de incendios = fireproof [fire-proof].

* a prueba de inendios = fireproof [fire-proof].

* a prueba de niños = childproof.

* a prueba de robos = theft proof.

* a prueba de tornados = tornado proof.

* a prueba de un tratamiento duro = ruggedised [ruggedized, -USA].

* a prueba de viento = windproof.

* a toda prueba = unswerving.

* banco de pruebas = testbed [test bed], benchmarking.

* cada vez más pruebas = accumulating evidence.

* carga de la prueba, la = burden of proof, the.

* chaleco a prueba de balas = bullet-proof vest.

* como prueba de = as a token of, as a sign of.

* como prueba de agradecimiento = as a token of thanks.

* como prueba de + Posesivo + agradecimiento = as a token of + Posesivo + appreciation.

* como prueba de + Posesivo + gratitud = as a token of + Posesivo + gratitude.

* como pruebas = in evidence.

* corrección de pruebas = proofreading, proof correction.

* corrector de pruebas = proofreader, corrector.

* corregir pruebas = proof, proofread.

* corregir una prueba = correct + proof.

* dar pruebas = provide + evidence.

* demostrar Algo con pruebas = demonstrate + in print.

* de prueba = on a trial basis, trial, probationary, on trial.

* después de la prueba = posttest [post-test].

* durante un período de prueba = on a trial basis.

* encontrar pruebas = find + evidence.

* en prueba = on trial.

* existir pruebas de que = there + be + evidence that.

* falta de pruebas = lack of evidence to the contrary.

* hacer la prueba = give + it a whirl, give + it a shot, give + it a try.

* hacer pruebas = prove + trials.

* hacer una prueba = audition.

* haciendo pruebas = trial and error.

* las pruebas = the writing on the wall.

* lugar de prueba alfa = alpha test site, alpha site.

* lugar de prueba beta = beta test site.

* lugar de pruebas = test site.

* no superar la prueba de = not stand the test of.

* oferta de prueba = trial offer.

* pasar la prueba = pass + muster.

* pasar una prueba = endure + ordeal, pass + a test, stand up.

* pasar una prueba de sobra = pass with + flying colours.

* período de prueba = probationary period, trial period, trial run, probation, period of probation, probation period.

* peso de la prueba, el = burden of proof, the.

* poner Algo a prueba = push + Nombre + to + Posesivo + limits.

* poner a prueba = stretch, tax, try, strain, overtax, pilot, put to + the test, test, trial, overstretch, push + the envelope, put + Nombre + to the test, try + Nombre + on, push + Nombre + to the edge.

* poner a prueba la paciencia de un santo = test + Posesivo + patience, try + Nombre + patience, try + the patience of a saint.

* poner a prueba la paciencia de un santo = test + the patience of a saint.

* poner a prueba una idea = test + idea, pilot + idea.

* poseer pruebas = have + evidence.

* posterior a la prueba = post-test.

* presentar las pruebas ante = lay + evidence before.

* presentar pruebas = give + evidence.

* programa de prueba beta = beta test programme.

* proporcionar pruebas = provide + evidence.

* prueba beta = beta test.

* prueba cloze = cloze test.

* prueba concluyente = conclusive evidence.

* prueba de acidez = litmus test.

* prueba de alcoholemia = breath test, alcohol testing.

* prueba de antidopaje = drug testing.

* prueba de antidoping = drug testing.

* prueba decisiva = litmus test.

* prueba de compra = proof of purchase.

* prueba de desgaste = wear test.

* prueba de detección de consumo de drogas = drug testing.

* prueba de detección del cáncer = health facility, cancer screening.

* prueba de fuego, la = acid test, the.

* prueba de identidad = proof of identity.

* prueba de laboratorio = lab test.

* prueba de la densidad = density test.

* prueba de la máxima proximidad = nearest neighbour test.

* prueba del embarazo = pregnancy test.

* prueba del hecho de que = evidence of the fact that.

* prueba del solapamiento = overlap test.

* prueba de paternidad = paternity test.

* prueba de prensa = press proof.

* prueba de referencia = benchmark test.

* prueba de rendimiento = benchmark, benchtest, achievement test, performance test.

* prueba determinante = litmus test.

* prueba de tornasol = litmus test.

* prueba de validación = validation test.

* prueba documental = documentary evidence.

* prueba dura = ordeal.

* prueba evidente = living proof.

* prueba fehaciente = competent proof, living proof.

* prueba final = final.

* prueba inequívoca = ironclad proof.

* prueba in situ = field test.

* prueba nuclear = nuclear weapons testing.

* prueba palpable = living proof.

* prueba rápida = quiz form, quiz [quizzes, -pl.].

* pruebas = evidence, proofs, testing.

* pruebas cada vez más concluyentes = mounting evidence.

* pruebas circunstanciales = circumstantial evidence.

* pruebas contundentes = hard evidence.

* pruebas convincentes = convincing evidence.

* pruebas de rendimiento = benchmarking.

* pruebas en contra = evidence to the contrary.

* pruebas forenses = forensic evidence.

* pruebas indirectas = circumstantial evidence.

* prueba sobre el terreno = field test, field trial.

* pruebas previas = prior art.

* prueba univariante = univariate test.

* prueba viviente = living proof.

* puesta a prueba = trying, piloting.

* puesto a prueba = overstretched.

* realizar una prueba = conduct + trial, take + test.

* recoger pruebas = collect + evidence, gather + evidence, accumulate + evidence.

* resultados de pruebas = test data.

* sacar una prueba = pull + a proof.

* ser la prueba de fuego de Algo = test + Nombre + to the limit.

* ser prueba suficiente = be proof enough.

* ser una prueba más de = strengthen + evidence.

* someter a prueba = place + strain on.

* terreno de pruebas = testing ground.

* tira de prueba = test strip.

* versión de prueba = test drive, trial version.

* * *

1)

a) (demostración, testimonio) proof

b) (Der) piece of evidence

- prueba de compra

- pruebas materiales

2) (Educ) test; (Cin) screen test, audition; (Teatr) audition

- prueba de aptitud

- prueba de fuego

3)

a) (ensayo, experimento)

b) ( circunstancia difícil)

c) (en locs)

d) ( en costura) fitting

- prueba de laboratorio

- prueba del alcohol or de la alcoholemia

- prueba del embarazo

- prueba nuclear

4) (Fot, Impr) proof

5) (Dep)

pruebas, etc see probar

* * *

* * *

(demostración, señal): te ha llamado, eso es prueba de que le caes bien he called you, that shows o that proves he likes you, he called you, that's a sure sign that he likes you

no había estudiado nada, la prueba está en que no contestó ni una pregunta it was quite clear o evident that he hadn't done any studying, he didn't answer a single question

dio constantes pruebas de su lealtad he proved his loyalty over and over again

no dio la menor prueba de estar sufriendo he didn't give the slightest hint o indication that he was suffering

acepta este regalo en or como prueba de mi agradecimiento accept this gift as a token of my gratitude

2 ( Der)

(cosa, argumento): retiraron la acusación por falta de pruebas the charge was withdrawn owing to lack of evidence

no hay pruebas de que eso sea verdad there's no proof that that's true

tendrá que presentar pruebas de ello he will have to provide evidence to prove it, he'll have to prove it

esta nueva prueba this new (piece of) evidence

esto es prueba concluyente de que nos mintió this is conclusive proof that he lied to us

a las pruebas me remito this/that proves it

3 ( Mat):

hacer la prueba de una operación to check one's calculations

circumstantial evidence

proof of purchase

la prueba del absurdo reductio ad absurdum

fpl material evidence

B ( Educ) test; ( Cin) screen test, audition; ( Teatr) audition

aptitude test

acid test

es un papel verdaderamente difícil, que va a ser su prueba de fuego como actor it's a really difficult part, which will be the acid test of his acting ability

placement test, grading test

(ensayo, experimento): ¿qué pasa si aprietas este botón? — no sé, hagamos la prueba what happens if you press this button? — I don't know, let's try it and see

¿por qué no haces la prueba de dejarlo en remojo? why don't you try leaving it to soak?

¡mira que te pego! — ¿a ver? ¡haz la prueba! (CS fam); I'll hit you! — oh yeah? let's see you try! ( colloq)

2 ( en locs):

a prueba: no tenía experiencia pero lo tomaron a prueba he had no experience but they took him on for a trial period o on probation

tenemos esta fotocopiadora a prueba we have this photocopier on trial

llévelo a prueba take it on trial o on approval

poner algo a prueba to put sth to the test

estás poniendo a prueba mi paciencia you're trying my patience

a prueba de: un reloj a prueba de golpes a shockproof watch

un dispositivo a prueba de ladrones a burglarproof mechanism

a prueba de niños ( hum); childproof

cristal a prueba de balas bulletproof glass

dio unos argumentos a prueba de balas she put forward some rock solid o cast-iron arguments

3 (en costura) fitting

laboratory trial o test

Breathalyzer® test, sobriety test ( AmE), drunkometer test ( AmE)

pregnancy test

nuclear test

benchmark

hacer la prueba patrón or de referencia to benchmark

fpl weapons testing

D ( Fot, Impr) proof

corregir pruebas to proofread

artist's proof

galley proof

1 ( Dep):

en las pruebas de clasificación in the qualifying heats

la prueba de los 1.500 metros the 1,500 meters event o race, the 1,500 meters

las pruebas de descenso the downhill events

2 ( AmL) (ejercicio) feat, act

road race

probar

* * *

3ª persona singular (él/ella/usted) presente indicativo

2ª persona singular (tú) imperativo

a) ‹vino/sopa› to taste;

b) ‹ método› to try;

c) ‹ ropa› to try on;

d) ( poner a prueba) ‹empleado/honradez› to test;

a) (demostración, testimonio) proof;

◊ no hay pruebas de que eso sea verdad there's no proof that that's true;

b) (Der) piece of evidence

a) (ensayo, experimento) test;

◊ vamos a hacer la prueba let's try;

b) ( en locs)

◊ a prueba: tomar a algn a prueba to take sb on for a trial period;

c) ( en costura) fitting

◊ corregir pruebas to proofread

◊ en las pruebas de clasificación in the qualifying heats;

* * *

♦ ver probar

♦ nf

1. [demostración] proof;

no existe ninguna prueba de que haya copiado en el examen there is no proof that he copied during the exam;

dio pruebas irrefutables de que era inocente she gave irrefutable proof of her innocence, she proved beyond doubt that she was innocent;

no tengo pruebas I have no proof;

¡ahí tienes la prueba! that proves it!

2. Der piece of evidence;

pruebas evidence, proof;

fue absuelto por falta de pruebas he was acquitted owing to a lack of evidence;

presentar pruebas to submit evidence;

a las pruebas me remito the evidence will bear me out

pruebas de indicios circumstantial evidence;

pruebas instrumentales documentary evidence

3. [manifestación, señal] sign;

eso es prueba de que les importa this proves they care, this is a sign that they care;

a mitad de carrera empezó a dar pruebas de cansancio halfway through the race she started to show signs of tiring;

en o [m5] como prueba de mi amistad in o as proof of friendship;

le hice el regalo como prueba de agradecimiento/mi amor I gave her the present as a token of my gratitude/love

4. [examen académico] test;

el examen consta de una prueba escrita y otra oral the exam has an oral part and a written part

prueba de aptitud aptitude test

5. [comprobación, ensayo, experimento] test;

hicimos la prueba de cambiar las pilas we tried changing the batteries;

¡haga usted la prueba! try it and see!;

hacerle a alguien una prueba to test sb, to give sb a test;

hacer la prueba: te voy a abandonar para siempre – hacé la prueba I'm going to walk out and leave you for good – go on, then!

prueba del alcohol Breathalyser® test;

hacer la prueba del alcohol a alguien to breathalyse sb;

prueba de (la) alcoholemia Br Breathalyser® o US drunkometer test;

prueba antidopaje drugs test;

prueba antidoping drugs test;

hacer la prueba antidoping a alguien to test sb for drugs;

prueba del embarazo pregnancy test;

hacerse la prueba del embarazo to take a pregnancy test;

prueba nuclear nuclear test;

pruebas nucleares nuclear testing;

prueba de (la) paternidad paternity test;

prueba de resistencia endurance test;

la prueba del sida AIDS test;

hacerle a alguien la prueba del sida to test sb for AIDS;

hacerse la prueba del sida to have an AIDS test;

prueba de sonido sound check

6. [trance] ordeal, trial;

la distancia fue una dura prueba para su relación being separated really put their relationship to the test

7. Dep event;

la prueba de los 110 metros vallas the 110 metres hurdles;

la prueba de lanzamiento de jabalina the javelin;

una prueba ciclista a cycling race

prueba clasificatoria heat;

prueba eliminatoria heat;

prueba de saltos [de equitación] show jumping (competition)

8. Imprenta proof;

corregir pruebas, hacer corrección de pruebas to proofread

9. Fot prueba negativa negative;

prueba positiva print

10. Am [ejercicio] acrobatic feat

♦ a prueba loc adj

poner a prueba la paciencia de alguien to try sb's patience;

poner algo/a alguien a prueba to put sth/sb to the test;

fe a toda prueba unshakeable faith;

* * *

1 tb TIP proof;

en prueba de as proof of;

dar pruebas de prove, give proof of

2 JUR piece of evidence;

por falta de pruebas for lack of evidence

3 DEP event

4 EDU test;

prueba de acceso o

admisión entrance exam

5 resistencia

a prueba de bala bulletproof;

a prueba de agua waterproof;

a prueba de aire airtight;

a prueba de fuego fireproof;

a prueba de choques shock-resistant;

poner algo a prueba put sth to the test

* * *

prueba, etc. probar

prueba nf

1) : proof, evidence

2) : trial, test

3) : proof (in printing or photography)

4) : event, qualifying round (in sports)

a prueba de agua : waterproof

prueba de fuego : acid test

poner a prueba : to put to the test

* * *

prueba n

1. (examen, análisis) test

2. (en deportes) event

3. (testimonio) proof

poner a prueba to put to the test [pt. & pp. put]

SUBJECT AREA: Land transport, Railways and locomotives

[br]

[br]

[br]

George Stephenson was the son of the fireman of the pumping engine at Wylam colliery, and horses drew wagons of coal along the wooden rails of the Wylam wagonway past the house in which he was born and spent his earliest childhood. While still a child he worked as a cowherd, but soon moved to working at coal pits. At 17 years of age he showed sufficient mechanical talent to be placed in charge of a new pumping engine, and had already achieved a job more responsible than that of his father. Despite his position he was still illiterate, although he subsequently learned to read and write. He was largely self-educated.

In 1801 he was appointed Brakesman of the winding engine at Black Callerton pit, with responsibility for lowering the miners safely to their work. Then, about two years later, he became Brakesman of a new winding engine erected by Robert Hawthorn at Willington Quay on the Tyne. Returning collier brigs discharged ballast into wagons and the engine drew the wagons up an inclined plane to the top of "Ballast Hill" for their contents to be tipped; this was one of the earliest applications of steam power to transport, other than experimentally.

In 1804 Stephenson moved to West Moor pit, Killingworth, again as Brakesman. In 1811 he demonstrated his mechanical skill by successfully modifying a new and unsatisfactory atmospheric engine, a task that had defeated the efforts of others, to enable it to pump a drowned pit clear of water. The following year he was appointed Enginewright at Killingworth, in charge of the machinery in all the collieries of the "Grand Allies", the prominent coal-owning families of Wortley, Liddell and Bowes, with authorization also to work for others. He built many stationary engines and he closely examined locomotives of John Blenkinsop's type on the Kenton \& Coxlodge wagonway, as well as those of William Hedley at Wylam.

It was in 1813 that Sir Thomas Liddell requested George Stephenson to build a steam locomotive for the Killingworth wagonway: Blucher made its first trial run on 25 July 1814 and was based on Blenkinsop's locomotives, although it lacked their rack-and-pinion drive. George Stephenson is credited with building the first locomotive both to run on edge rails and be driven by adhesion, an arrangement that has been the conventional one ever since. Yet Blucher was far from perfect and over the next few years, while other engineers ignored the steam locomotive, Stephenson built a succession of them, each an improvement on the last.

During this period many lives were lost in coalmines from explosions of gas ignited by miners' lamps. By observation and experiment (sometimes at great personal risk) Stephenson invented a satisfactory safety lamp, working independently of the noted scientist Sir Humphry Davy who also invented such a lamp around the same time.

In 1817 George Stephenson designed his first locomotive for an outside customer, the Kilmarnock \& Troon Railway, and in 1819 he laid out the Hetton Colliery Railway in County Durham, for which his brother Robert was Resident Engineer. This was the first railway to be worked entirely without animal traction: it used inclined planes with stationary engines, self-acting inclined planes powered by gravity, and locomotives.

On 19 April 1821 Stephenson was introduced to Edward Pease, one of the main promoters of the Stockton \& Darlington Railway (S \& DR), which by coincidence received its Act of Parliament the same day. George Stephenson carried out a further survey, to improve the proposed line, and in this he was assisted by his 18-year-old son, Robert Stephenson, whom he had ensured received the theoretical education which he himself lacked. It is doubtful whether either could have succeeded without the other; together they were to make the steam railway practicable.

At George Stephenson's instance, much of the S \& DR was laid with wrought-iron rails recently developed by John Birkinshaw at Bedlington Ironworks, Morpeth. These were longer than cast-iron rails and were not brittle: they made a track well suited for locomotives. In June 1823 George and Robert Stephenson, with other partners, founded a firm in Newcastle upon Tyne to build locomotives and rolling stock and to do general engineering work: after its Managing Partner, the firm was called Robert Stephenson \& Co.

In 1824 the promoters of the Liverpool \& Manchester Railway (L \& MR) invited George Stephenson to resurvey their proposed line in order to reduce opposition to it. William James, a wealthy land agent who had become a visionary protagonist of a national railway network and had seen Stephenson's locomotives at Killingworth, had promoted the L \& MR with some merchants of Liverpool and had carried out the first survey; however, he overreached himself in business and, shortly after the invitation to Stephenson, became bankrupt. In his own survey, however, George Stephenson lacked the assistance of his son Robert, who had left for South America, and he delegated much of the detailed work to incompetent assistants. During a devastating Parliamentary examination in the spring of 1825, much of his survey was shown to be seriously inaccurate and the L \& MR's application for an Act of Parliament was refused. The railway's promoters discharged Stephenson and had their line surveyed yet again, by C.B. Vignoles.

The Stockton \& Darlington Railway was, however, triumphantly opened in the presence of vast crowds in September 1825, with Stephenson himself driving the locomotive Locomotion, which had been built at Robert Stephenson \& Co.'s Newcastle works. Once the railway was at work, horse-drawn and gravity-powered traffic shared the line with locomotives: in 1828 Stephenson invented the horse dandy, a wagon at the back of a train in which a horse could travel over the gravity-operated stretches, instead of trotting behind.

Meanwhile, in May 1826, the Liverpool \& Manchester Railway had successfully obtained its Act of Parliament. Stephenson was appointed Engineer in June, and since he and Vignoles proved incompatible the latter left early in 1827. The railway was built by Stephenson and his staff, using direct labour. A considerable controversy arose c. 1828 over the motive power to be used: the traffic anticipated was too great for horses, but the performance of the reciprocal system of cable haulage developed by Benjamin Thompson appeared in many respects superior to that of contemporary locomotives. The company instituted a prize competition for a better locomotive and the Rainhill Trials were held in October 1829.

Robert Stephenson had been working on improved locomotive designs since his return from America in 1827, but it was the L \& MR's Treasurer, Henry Booth, who suggested the multi-tubular boiler to George Stephenson. This was incorporated into a locomotive built by Robert Stephenson for the trials: Rocket was entered by the three men in partnership. The other principal entrants were Novelty, entered by John Braithwaite and John Ericsson, and Sans Pareil, entered by Timothy Hackworth, but only Rocket, driven by George Stephenson, met all the organizers' demands; indeed, it far surpassed them and demonstrated the practicability of the long-distance steam railway. With the opening of the Liverpool \& Manchester Railway in 1830, the age of railways began.

Stephenson was active in many aspects. He advised on the construction of the Belgian State Railway, of which the Brussels-Malines section, opened in 1835, was the first all-steam railway on the European continent. In England, proposals to link the L \& MR with the Midlands had culminated in an Act of Parliament for the Grand Junction Railway in 1833: this was to run from Warrington, which was already linked to the L \& MR, to Birmingham. George Stephenson had been in charge of the surveys, and for the railway's construction he and J.U. Rastrick were initially Principal Engineers, with Stephenson's former pupil Joseph Locke under them; by 1835 both Stephenson and Rastrick had withdrawn and Locke was Engineer-in-Chief. Stephenson remained much in demand elsewhere: he was particularly associated with the construction of the North Midland Railway (Derby to Leeds) and related lines. He was active in many other places and carried out, for instance, preliminary surveys for the Chester \& Holyhead and Newcastle \& Berwick Railways, which were important links in the lines of communication between London and, respectively, Dublin and Edinburgh.

He eventually retired to Tapton House, Chesterfield, overlooking the North Midland. A man who was self-made (with great success) against colossal odds, he was ever reluctant, regrettably, to give others their due credit, although in retirement, immensely wealthy and full of honour, he was still able to mingle with people of all ranks.

[br]

SUBJECT AREA: Photography, film and optics

[br]

[br]

[br]

Dickson was born in France of English and Scottish parents. As a young man of almost 19 years, he wrote in 1879 to Thomas Edison in America, asking for a job. Edison replied that he was not taking on new staff at that time, but Dickson, with his mother and sisters, decided to emigrate anyway. In 1883 he contacted Edison again, and was given a job at the Goerk Street laboratory of the Edison Electric Works in New York. He soon assumed a position of responsibility as Superintendent, working on the development of electric light and power systems, and also carried out most of the photography Edison required. In 1888 he moved to the Edison West Orange laboratory, becoming Head of the ore-milling department. When Edison, inspired by Muybridge's sequence photographs of humans and animals in motion, decided to develop a motion picture apparatus, he gave the task to Dickson, whose considerable skills in mechanics, photography and electrical work made him the obvious choice. The first experiments, in 1888, were on a cylinder machine like the phonograph, in which the sequence pictures were to be taken in a spiral. This soon proved to be impractical, and work was delayed for a time while Dickson developed a new ore-milling machine. Little progress with the movie project was made until George Eastman's introduction in July 1889 of celluloid roll film, which was thin, tough, transparent and very flexible. Dickson returned to his experiments in the spring of 1891 and soon had working models of a film camera and viewer, the latter being demonstrated at the West Orange laboratory on 20 May 1891. By the early summer of 1892 the project had advanced sufficiently for commercial exploitation to begin. The Kinetograph camera used perforated 35 mm film (essentially the same as that still in use in the late twentieth century), and the kinetoscope, a peep-show viewer, took fifty feet of film running in an endless loop. Full-scale manufacture of the viewers started in 1893, and they were demonstrated on a number of occasions during that year. On 14 April 1894 the first kinetoscope parlour, with ten viewers, was opened to the public in New York. By the end of that year, the kinetoscope was seen by the public all over America and in Europe. Dickson had created the first commercially successful cinematograph system. Dickson left Edison's employment on 2 April 1895, and for a time worked with Woodville Latham on the development of his Panoptikon projector, a projection version of the kinetoscope. In December 1895 he joined with Herman Casier, Henry N.Marvin and Elias Koopman to form the American Mutoscope Company. Casier had designed the Mutoscope, an animated-picture viewer in which the sequences of pictures were printed on cards fixed radially to a drum and were flipped past the eye as the drum rotated. Dickson designed the Biograph wide-film camera to produce the picture sequences, and also a projector to show the films directly onto a screen. The large-format images gave pictures of high quality for the period; the Biograph went on public show in America in September 1896, and subsequently throughout the world, operating until around 1905. In May 1897 Dickson returned to England and set up as a producer of Biograph films, recording, among other subjects, Queen Victoria's Diamond Jubilee celebrations in 1897, Pope Leo XIII in 1898, and scenes of the Boer War in 1899 and 1900. Many of the Biograph subjects were printed as reels for the Mutoscope to produce the "what the butler saw" machines which were a feature of fairgrounds and seaside arcades until modern times. Dickson's contact with the Biograph Company, and with it his involvement in cinematography, ceased in 1911.

[br]

SUBJECT AREA: Electricity, Electronics and information technology, Photography, film and optics

[br]

[br]

[br]

Paul was educated at the City of London School and Finsbury Technical College. He worked first for a short time in the Bell Telephone Works in Antwerp, Belgium, and then in the electrical instrument shop of Elliott Brothers in the Strand until 1891, when he opened an instrument-making business at 44 Hatton Garden, London. He specialized in the design and manufacture of electrical instruments, including the Ayrton Mather galvanometer. In 1902, with a purpose-built factory, he began large batch production of his instruments. He also opened a factory in New York, where uncalibrated instruments from England were calibrated for American customers. In 1903 Paul introduced the Unipivot galvanometer, in which the coil was supported at the centre of gravity of the moving system on a single pivot. The pivotal friction was less than in a conventional instrument and could be used without accurate levelling, the sensitivity being far beyond that of any pivoted galvanometer then in existence.

In 1894 Paul was asked by two entrepreneurs to make copies of Edison's kinetoscope, the pioneering peep-show moving-picture viewer, which had just arrived in London. Discovering that Edison had omitted to patent the machine in England, and observing that there was considerable demand for the machine from show-people, he began production, making six before the end of the year. Altogether, he made about sixty-six units, some of which were exported. Although Edison's machine was not patented, his films were certainly copyrighted, so Paul now needed a cinematographic camera to make new subjects for his customers. Early in 1895 he came into contact with Birt Acres, who was also working on the design of a movie camera. Acres's design was somewhat impractical, but Paul constructed a working model with which Acres filmed the Oxford and Cambridge Boat Race on 30 March, and the Derby at Epsom on 29 May. Paul was unhappy with the inefficient design, and developed a new intermittent mechanism based on the principle of the Maltese cross. Despite having signed a ten-year agreement with Paul, Acres split with him on 12 July 1895, after having unilaterally patented their original camera design on 27 May. By the early weeks of 1896, Paul had developed a projector mechanism that also used the Maltese cross and which he demonstrated at the Finsbury Technical College on 20 February 1896. His Theatrograph was intended for sale, and was shown in a number of venues in London during March, notably at the Alhambra Theatre in Leicester Square. There the renamed Animatographe was used to show, among other subjects, the Derby of 1896, which was won by the Prince of Wales's horse "Persimmon" and the film of which was shown the next day to enthusiastic crowds. The production of films turned out to be quite profitable: in the first year of the business, from March 1896, Paul made a net profit of £12,838 on a capital outlay of about £1,000. By the end of the year there were at least five shows running in London that were using Paul's projectors and screening films made by him or his staff.

Paul played a major part in establishing the film business in England through his readiness to sell apparatus at a time when most of his rivals reserved their equipment for sole exploitation. He went on to become a leading producer of films, specializing in trick effects, many of which he pioneered. He was affectionately known in the trade as "Daddy Paul", truly considered to be the "father" of the British film industry. He continued to appreciate fully the possibilities of cinematography for scientific work, and in collaboration with Professor Silvanus P.Thompson films were made to illustrate various phenomena to students.

Paul ended his involvement with film making in 1910 to concentrate on his instrument business; on his retirement in 1920, this was amalgamated with the Cambridge Instrument Company. In his will he left shares valued at over £100,000 to form the R.W.Paul Instrument Fund, to be administered by the Institution of Electrical Engineers, of which he had been a member since 1887. The fund was to provide instruments of an unusual nature to assist physical research.

[br]

BC / GW

SUBJECT AREA: Land transport, Railways and locomotives

[br]

[br]

[br]

Robert Stephenson's father was George Stephenson, who ensured that his son was educated to obtain the theoretical knowledge he lacked himself. In 1821 Robert Stephenson assisted his father in his survey of the Stockton \& Darlington Railway and in 1822 he assisted William James in the first survey of the Liverpool \& Manchester Railway. He then went to Edinburgh University for six months, and the following year Robert Stephenson \& Co. was named after him as Managing Partner when it was formed by himself, his father and others. The firm was to build stationary engines, locomotives and railway rolling stock; in its early years it also built paper-making machinery and did general engineering.

In 1824, however, Robert Stephenson accepted, perhaps in reaction to an excess of parental control, an invitation by a group of London speculators called the Colombian Mining Association to lead an expedition to South America to use steam power to reopen gold and silver mines. He subsequently visited North America before returning to England in 1827 to rejoin his father as an equal and again take charge of Robert Stephenson \& Co. There he set about altering the design of steam locomotives to improve both their riding and their steam-generating capacity. Lancashire Witch, completed in July 1828, was the first locomotive mounted on steel springs and had twin furnace tubes through the boiler to produce a large heating surface. Later that year Robert Stephenson \& Co. supplied the Stockton \& Darlington Railway with a wagon, mounted for the first time on springs and with outside bearings. It was to be the prototype of the standard British railway wagon. Between April and September 1829 Robert Stephenson built, not without difficulty, a multi-tubular boiler, as suggested by Henry Booth to George Stephenson, and incorporated it into the locomotive Rocket which the three men entered in the Liverpool \& Manchester Railway's Rainhill Trials in October. Rocket, was outstandingly successful and demonstrated that the long-distance steam railway was practicable.

Robert Stephenson continued to develop the locomotive. Northumbrian, built in 1830, had for the first time, a smokebox at the front of the boiler and also the firebox built integrally with the rear of the boiler. Then in Planet, built later the same year, he adopted a layout for the working parts used earlier by steam road-coach pioneer Goldsworthy Gurney, placing the cylinders, for the first time, in a nearly horizontal position beneath the smokebox, with the connecting rods driving a cranked axle. He had evolved the definitive form for the steam locomotive.

Also in 1830, Robert Stephenson surveyed the London \& Birmingham Railway, which was authorized by Act of Parliament in 1833. Stephenson became Engineer for construction of the 112-mile (180 km) railway, probably at that date the greatest task ever undertaken in of civil engineering. In this he was greatly assisted by G.P.Bidder, who as a child prodigy had been known as "The Calculating Boy", and the two men were to be associated in many subsequent projects. On the London \& Birmingham Railway there were long and deep cuttings to be excavated and difficult tunnels to be bored, notoriously at Kilsby. The line was opened in 1838.

In 1837 Stephenson provided facilities for W.F. Cooke to make an experimental electrictelegraph installation at London Euston. The directors of the London \& Birmingham Railway company, however, did not accept his recommendation that they should adopt the electric telegraph and it was left to I.K. Brunel to instigate the first permanent installation, alongside the Great Western Railway. After Cooke formed the Electric Telegraph Company, Stephenson became a shareholder and was Chairman during 1857–8.

Earlier, in the 1830s, Robert Stephenson assisted his father in advising on railways in Belgium and came to be increasingly in demand as a consultant. In 1840, however, he was almost ruined financially as a result of the collapse of the Stanhope \& Tyne Rail Road; in return for acting as Engineer-in-Chief he had unwisely accepted shares, with unlimited liability, instead of a fee.

During the late 1840s Stephenson's greatest achievements were the design and construction of four great bridges, as part of railways for which he was responsible. The High Level Bridge over the Tyne at Newcastle and the Royal Border Bridge over the Tweed at Berwick were the links needed to complete the East Coast Route from London to Scotland. For the Chester \& Holyhead Railway to cross the Menai Strait, a bridge with spans as long-as 460 ft (140 m) was needed: Stephenson designed them as wrought-iron tubes of rectangular cross-section, through which the trains would pass, and eventually joined the spans together into a tube 1,511 ft (460 m) long from shore to shore. Extensive testing was done beforehand by shipbuilder William Fairbairn to prove the method, and as a preliminary it was first used for a 400 ft (122 m) span bridge at Conway.

In 1847 Robert Stephenson was elected MP for Whitby, a position he held until his death, and he was one of the exhibition commissioners for the Great Exhibition of 1851. In the early 1850s he was Engineer-in-Chief for the Norwegian Trunk Railway, the first railway in Norway, and he also built the Alexandria \& Cairo Railway, the first railway in Africa. This included two tubular bridges with the railway running on top of the tubes. The railway was extended to Suez in 1858 and for several years provided a link in the route from Britain to India, until superseded by the Suez Canal, which Stephenson had opposed in Parliament. The greatest of all his tubular bridges was the Victoria Bridge across the River St Lawrence at Montreal: after inspecting the site in 1852 he was appointed Engineer-in-Chief for the bridge, which was 1 1/2 miles (2 km) long and was designed in his London offices. Sadly he, like Brunel, died young from self-imposed overwork, before the bridge was completed in 1859.

[br]

See also: Pihl, Carl Abraham; Seguin, Marc

SUBJECT AREA: Broadcasting, Electronics and information technology, Recording, Telecommunications

[br]

[br]

[br]

From an early age he was absorbed by phenomena of physics to the exclusion of all other subjects, including mathematics. When choosing his subjects for the final three years in Borgedydskolen in Christianshavn (Copenhagen) before university, he opted for languages and history. At the University of Copenhagen he embarked on the study of medicine in 1889, but broke it off and was apprenticed to the machine firm of A/S Frichs Eftf. in Aarhus. He was employed between 1893 and 1899 as a mechanic and assistant in the laboratory of the Copenhagen Telephone Company KTAS. Eventually he advanced to be Head of the line fault department. This suited his desire for experiment and measurement perfectly. After the invention of the telegraphone in 1898, he left the laboratory and with responsible business people he created Aktieselskabet Telegrafonen, Patent Poulsen in order to develop it further, together with Peder Oluf Pedersen (1874– 1941). Pedersen brought with him the mathematical background which eventually led to his professorship in electronic engineering in 1922.

The telegraphone was the basis for multinational industrial endeavours after it was demonstrated at the 1900 World's Exhibition in Paris. It must be said that its strength was also its weakness, because the telegraphone was unique in bringing sound recording and reproduction to the telephone field, but the lack of electronic amplifiers delayed its use outside this and the dictation fields (where headphones could be used) until the 1920s. However, commercial interest was great enough to provoke a number of court cases concerning patent infringement, in which Poulsen frequently figured as a witness.

In 1903–4 Poulsen and Pedersen developed the arc generator for continuous radio waves which was used worldwide for radio transmitters in competition with Marconi's spark-generating system. The inspiration for this work came from the research by William Duddell on the musical arc. Whereas Duddell had proposed the use of the oscillations generated in his electric arc for telegraphy in his 1901 UK patent, Poulsen contributed a chamber of hydrogen and a transverse magnetic field which increased the efficiency remarkably. He filed patent applications on these constructions from 1902 and the first publication in a scientific forum took place at the International Electrical Congress in St Louis, Missouri, in 1904.

In order to use continuous waves efficiently (the high frequency constituted a carrier), Poulsen developed both a modulator for telegraphy and a detector for the carrier wave. The modulator was such that even the more primitive spark-communication receivers could be used. Later Poulsen and Pedersen developed frequency-shift keying.

The Amalgamated Radio-Telegraph Company Ltd was launched in London in 1906, combining the developments of Poulsen and those of De Forest Wireless Telegraph Syndicate. Poulsen contributed his English and American patents. When this company was liquidated in 1908, its assets were taken over by Det Kontinentale Syndikat for Poulsen Radio Telegrafi, A/S in Copenhagen (liquidated 1930–1). Some of the patents had been sold to C.Lorenz AG in Berlin, which was very active.

The arc transmitting system was in use worldwide from about 1910 to 1925, and the power increased from 12 kW to 1,000 kW. In 1921 an exceptional transmitter rated at 1,800 kW was erected on Java for communications with the Netherlands. More than one thousand installations had been in use worldwide. The competing systems were initially spark transmitters (Marconi) and later rotary converters ( Westinghouse). Similar power was available from valve transmitters only much later.

From c. 1912 Poulsen did not contribute actively to further development. He led a life as a well-respected engineer and scientist and served on several committees. He had his private laboratory and made experiments in the composition of matter and certain resonance phenomena; however, nothing was published. It has recently been suggested that Poulsen could not have been unaware of Oberlin Smith's work and publication in 1888, but his extreme honesty in technical matters indicates that his development was indeed independent. In the case of the arc generator, Poulsen was always extremely frank about the inspiration he gained from earlier developers' work.

[br]

SUBJECT AREA: Civil engineering, Domestic appliances and interiors, Land transport, Mechanical, pneumatic and hydraulic engineering, Public utilities

[br]

[br]

[br]

Bramah was the son of a tenant farmer and was educated at the village school before being apprenticed to a local carpenter, Thomas Allot. He walked to London c.1773 and found work with a Mr Allen that included the repair of some of the comparatively rare water-closets of the period. He invented and patented one of his own, which was followed by a water cock in 1783. His next invention, a greatly improved lock, involved the devising of a number of special machine tools, for it was one of the first devices involving interchangeable components in its manufacture. In this he had the help of Henry Maudslay, then a young and unknown engineer, who became Bramah's foreman before setting up business on his own. In 1784 he moved his premises from Denmark Street, St Giles, to 124 Piccadilly, which was later used as a showroom when he set up a factory in Pimlico. He invented an engine for putting out fires in 1785 and 1793, in effect a reciprocating rotary-vane pump. He undertook the refurbishment and modernization of Norwich waterworks c.1793, but fell out with Robert Mylne, who was acting as Consultant to the Norwich Corporation and had produced a remarkably vague specification. This was Bramah's only venture into the field of civil engineering.

In 1797 he acted as an expert witness for Hornblower \& Maberley in the patent infringement case brought against them by Boulton and Watt. Having been cut short by the judge, he published his proposed evidence in "Letter to the Rt Hon. Sir James Eyre, Lord Chief Justice of the Common Pleas…etc". In 1795 he was granted his most important patent, based on Pascal's Hydrostatic Paradox, for the hydraulic press which also incorporated the concept of hydraulics for the transmission of both power and motion and was the foundation of the whole subsequent hydraulic industry. There is no truth in the oft-repeated assertion originating from Samuel Smiles's Industrial Biography (1863) that the hydraulic press could not be made to work until Henry Maudslay invented the self-sealing neck leather. Bramah used a single-acting upstroking ram, sealed only at its base with a U-leather. There was no need for a neck leather.

He also used the concept of the weight-loaded, in this case as a public-house beer-engine. He devised machinery for carbonating soda water. The first banknote-numbering machine was of his design and was bought by the Bank of England. His development of a machine to cut twelve nibs from one goose quill started a patent specification which ended with the invention of the fountain pen, patented in 1809. His coach brakes were an innovation that was followed bv a form of hydropneumatic carriage suspension that was somewhat in advance of its time, as was his patent of 1812. This foresaw the introduction of hydraulic power mains in major cities and included the telescopic ram and the air-loaded accumulator.

In all Joseph Bramah was granted eighteen patents. On 22 March 1813 he demonstrated a hydraulic machine for pulling up trees by the roots in Hyde Park before a large crowd headed by the Duke of York. Using the same machine in Alice Holt Forest in Hampshire to fell timber for ships for the Navy, he caught a chill and died soon after at his home in Pimlico.

[br]

SUBJECT AREA: Photography, film and optics

[br]

[br]

[br]

Edwin Land's career began when, as a Harvard undergraduate in the late 1920s, he became interested in the possibility of developing a polarizing filter in the form of a thin sheet, to replace the crystal and stacked-glass devices then in use, which were expensive, cumbersome and limited in size. He succeeded in creating a material in which minute anisotropic iodine crystals were oriented in line, producing an efficient polarizer that was patented in 1929. After presenting the result of his researches in a Physics Department colloquium at Harvard, he left to form a partnership with George Wheelwright to manufacture the new material, which was seen to have applications as diverse as anti-glare car headlights, sunglasses, and viewing filters for stereoscopic photographs and films. In 1937 he founded the Polaroid Corporation and developed the Vectograph process, in which self-polarized photographic images could be printed, giving a stereoscopic image when viewed through polarizing viewers. Land's most significant invention, the instant picture, was stimulated by his three-year-old daughter. As he took a snapshot of her, she asked why she could not see the picture at once. He began to research the possibility, and on 21 February 1947 he demonstrated a system of one-step photography at a meeting of the Optical Society of America. Using the principle of diffusion transfer of the image, it produced a photograph in one minute. The Polaroid Land camera was launched on 26 November 1948. The original sepia-coloured images were soon replaced by black and white and, in 1963, by Polacolor instant colour film. The original peel-apart "wet" process was superseded in 1972 with the introduction of the SX-70 camera with dry picture units which developed in the light. The instant colour movie system Polavision, introduced in 1978, was less successful and was one of his few commercial failures.

Land died in March 1991, after a career in which he had been honoured by countless scien-tific and academic bodies and had received the Medal of Freedom, the highest civilian honour in America.

[br]

SUBJECT AREA: Photography, film and optics

[br]

[br]

[br]

The son of a tax collector, Ducos du Hauron began researches into colour photography soon after the publication of Clerk Maxwell's experiment in 1861. In a communication sent in 1862 for presentation at the Académie des Sciences, but which was never read, he outlined a number of methods for photography of colours. Subsequently, in his book Les Couleurs en photographie, published in 1869, he outlined most of the principles of additive and subtractive colour photography that were later actually used. He covered additive processes, developed from Clerk Maxwell's demonstrations, and subtractive processes which could yield prints. At the time, the photographic materials available prevented the processes from being employed effectively. The design of his Chromoscope, in which transparent reflectors could be used to superimpose three additive images, was sound, however, and formed the basis of a number of later devices. He also proposed an additive system based on the use of a screen of fine red, yellow and blue lines, through which the photograph was taken and viewed. The lines blended additively when seen from a certain distance. Many years later, in 1907, Ducos du Hauron was to use this principle in an early commercial screen-plate process, Omnicolore. With his brother Alcide, he published a further work in 1878, Photographie des Couleurs, which described some more-practical subtractive processes. A few prints made at this time still survive and they are remarkably good for the period. In a French patent of 1895 he described yet another method for colour photography. His "polyfolium chromodialytique" involved a multiple-layer package of separate red-, green-and blue-sensitive materials and filters, which with a single exposure would analyse the scene in terms of the three primary colours. The individual layers would be separated for subsequent processing and printing. In a refined form, this is the principle behind modern colour films. In 1891 he patented and demonstrated the anaglyph method of stereoscopy, using superimposed red and green left and right eye images viewed through green and red filters. Ducos du Hauron's remarkable achievement was to propose theories of virtually all the basic methods of colour photography at a time when photographic materials were not adequate for the purpose of proving them correct. For his work on colour photography he was awarded the Progress Medal of the Royal Photographic Society in 1900, but despite his major contributions to colour photography he remained in poverty for much of his later life.

[br]

SUBJECT AREA: Metallurgy, Ports and shipping

[br]

[br]

[br]

The son of a merchant of Dundee, Kirkaldy was educated there, then at Merchiston Castle School, Edinburgh, and at Edinburgh University. For a while he worked in his father's office, but with a preference for engineering, in 1843 he commenced an apprenticeship at the Glasgow works of Robert Napier. After four years in the shops he was transferred to the drawing office and in a very few years rose to become Chief. Here Kirkaldy demonstrated a remarkable talent both for the meticulous recording of observations and data and for technical drawing. His work also had an aesthetic appeal and four of his drawings of Napier steamships were shown at the Paris Exhibition of 1855, earning both Napier and Kirkaldy a medal. His "as fitted" set of drawings of the Cunard Liner Persia, which had been built in 1855, is now in the possession of the National Maritime Museum at Greenwich, London; it is regarded as one of the finest examples of its kind in the world, and has even been exhibited at the Royal Academy in London.

With the impending order for the Royal Naval Ironclad Black Prince (sister ship to HMS Warrior, now preserved at Portsmouth) and for some high-pressure marine boilers and engines, there was need for a close scientific analysis of the physical properties of iron and steel. Kirkaldy, now designated Chief Draughtsman and Calculator, was placed in charge of this work, which included comparisons of puddled steel and wrought iron, using a simple lever-arm testing machine. The tests lasted some three years and resulted in Kirkaldy's most important publication, Experiments on Wrought Iron and Steel (1862, London), which gained him wide recognition for his careful and thorough work. Napier's did not encourage him to continue testing; but realizing the growing importance of materials testing, Kirkaldy resigned from the shipyard in 1861. For the next two and a half years Kirkaldy worked on the design of a massive testing machine that was manufactured in Leeds and installed in premises in London, at The Grove, Southwark.

The works was open for trade in January 1866 and engineers soon began to bring him specimens for testing on the great machine: Joseph Cubitt (son of William Cubitt) brought him samples of the materials for the new Blackfriars Bridge, which was then under construction. Soon The Grove became too cramped and Kirkaldy moved to 99 Southwark Street, reopening in January 1874. In the years that followed, Kirkaldy gained a worldwide reputation for rigorous and meticulous testing and recording of results, coupled with the highest integrity. He numbered the most distinguished engineers of the time among his clients.

After Kirkaldy's death, his son William George, whom he had taken into partnership, carried on the business. When the son died in 1914, his widow took charge until her death in 1938, when the grandson David became proprietor. He sold out to Treharne \& Davies, chemical consultants, in 1965, but the works finally closed in 1974. The future of the premises and the testing machine at first seemed threatened, but that has now been secured and the machine is once more in working order. Over almost one hundred years of trading in South London, the company was involved in many famous enquiries, including the analysis of the iron from the ill-fated Tay Bridge (see Bouch, Sir Thomas).

[br]

LRD / FMW

SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

[br]

[br]

[br]

Little is known of the early years of Savery's life and no trace has been found that he served in the Army, so the title "Captain" is thought to refer to some mining appointment, probably in the West of England. He may have been involved in the Glorious Revolution of 1688, for later he was well known to William of Orange. From 1705 to 1714 he was Treasurer for Sick and Wounded Seamen, and in 1714 he was appointed Surveyor of the Water Works at Hampton Court, a post he held until his death the following year. He was interested in mechanical devices; amongst his early contrivances was a clock.

He was the most prolific inventor of his day, applying for seven patents, including one in 1649, for polishing plate glass which may have been used. His idea for 1697 for propelling ships with paddle-wheels driven by a capstan was a failure, although regarded highly by the King, and was published in his first book, Navigation Improved (1698). He tried to patent a new type of floating mill in 1707, and an idea in 1710 for baking sea coal or other fuel in an oven to make it clean and pure.

His most famous invention, however, was the one patented in 1698 "for raising water by the impellent force of fire" that Savery said would drain mines or low-lying land, raise water to supply towns or houses, and provide a source of water for turning mills through a water-wheel. Basically it consisted of a receiver which was first filled with steam and then cooled to create a vacuum by having water poured over the outside. The water to be pumped was drawn into the receiver from a lower sump, and then high-pressure steam was readmitted to force the water up a pipe to a higher level. It was demonstrated to the King and the Royal Society and achieved some success, for a few were installed in the London area and a manufactory set up at Salisbury Court in London. He published a book, The Miner's Friend, about his engine in 1702, but although he made considerable improvements, due to excessive fuel consumption and materials which could not withstand the steam pressures involved, no engines were installed in mines as Savery had hoped. His patent was extended in 1699 until 1733 so that it covered the atmospheric engine of Thomas Newcomen who was forced to join Savery and his other partners to construct this much more practical engine.

[br]