Biographical Dictionary of the History of Technology

By Lance Day; Ian McNeil | Go to book overview

D

Daft, Leo

b. 13 November 1843 Birmingham, England

d. 28 March 1922


English electrical engineer, pioneer of electric-power generation and electric railways in the USA.

Leo Daft, son of a British civil engineer, studied electricity and emigrated to the USA in 1866. After various occupations including running a photographic studio, he joined in 1879 the New York Electric Light Company, which was soon merged into the Daft Electric Company. This company developed electrically powered machinery and built electric-power plants. In 1883 Daft built an electric locomotive called Ampere for the Saratoga & Mount McGregor Railroad. This is said to have been the first electric main-line locomotive for standard gauge. It collected current from a central rail, had an output of 12 hp (9 kW) and hauled 10 tons at speeds up to 9 mph (14.5 km/h). Two years later Daft made a much improved locomotive for the New York Elevated Railway, the Benjamin Franklin, which drew current at 250 volts from a central rail and had two 48 in. (122 cm)-diameter driving wheels and two 33 in. (84 cm)-diameter trailing wheels. Re-equipped in 1888 with four driving wheels and a 125 hp (93 kW) motor, this could haul an eight-car train at 10 mph (16 km/h). Meanwhile, in 1884, Daft's company had manufactured all the electrical apparatus for the Massachusetts Electric Power Company, the first instance of a complete central station to generate and distribute electricity for power on a commercial scale. In 1885 it electrified a branch of the Baltimore Union Passenger Railway, the first electrically operated railway in the USA. Subsequently Daft invented a process for vulcanizing rubber onto metal that came into general use. He never became an American citizen.


Further Reading
Dictionary of American Biography.
F.J.G. Haut, 1969, The History of the Electric Locomotive, London: George Allen & Unwin.

See also Siemens, Dr Ernst Werner von.

PJGR


Dagron, Prudent René-Patrice

b. 1819 Beaumont, France

d. June 1900 Paris, France


French photographer who specialized in microphotography.

Dagron studied chemistry, but little else is known of his early career. He was the proprietor of a Paris shop selling stationery and office equipment in 1860, when he proposed making microscopic photographs mounted in jewellery. Dagron went on to produce examples using equipment constructed by the optician Debozcq. In 1864 Dagron became one of the celebrities of the day when he recorded 450 portraits on a single photograph that measured 1 mm3. The image was viewed by means of a tiny magnifying lens popularly known as a 'Stanhope' after its supposed inventor, the English Lord Charles Stanhope. The great demand for Stanhoped jewellery soon allowed Dagron to build a factory for its manufacture. Dagron's main claim to fame rests on his work during the Franco-Prussian War. At the siege of Paris, Dagron was ballooned out of the city to organize a carrier-pigeon communication service. Thousands of microphotographed dispatches could be carried by a single pigeon, and Dagron set up a regular service between Paris and Tours. In Paris the messages from the outside world were enlarged and projected onto a white wall and transcribed by a team of clerks. After the war, Dagron dabbled in aerial photography from balloons, but his interest in microphotography continued until his death in 1900.


Further Reading
G. Tissandier, 1874, Les Merveilles de la

-187-

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Biographical Dictionary of the History of Technology
Table of contents

Table of contents

  • Title Page iii
  • Contents v
  • Preface ix
  • Acknowledgements xi
  • How to Use the Dictionary xiii
  • A 1
  • B 33
  • C 122
  • D 187
  • E 228
  • F 247
  • G 277
  • H 315
  • German Organic Chemist. 347
  • I 368
  • J 374
  • K 391
  • L 412
  • Bibliography 418
  • M 451
  • N 513
  • O 528
  • P 535
  • Q 582
  • R 583
  • S 619
  • T 689
  • U 721
  • V 722
  • W 734
  • X 778
  • Y 779
  • Z 785
  • Index by Subject Area 790
  • Index of Topics 808
  • Index of Names 823
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