Figure 54. — Davenport's model of an electric 

 "train." The circular track is 4 feet in 

 diameter. {US JVM 181 82^; Smithsonian photo 

 38403-) 





Figure 55. — Patent Office model of Davenport's 

 electric motor. (USNM 2^2644; Smithsonian 

 bhoto 44gy8.) 



Figure 56. — Davidson's motor. From Electrical 

 World, 1890, vol. 16, p. 277, fig. 2. 



Figure 57. — Davidson's electric locomotive. 

 From T. du Moncel, Electricity as a Motive 

 Power, London, 1883, fig. 32. 



and he had to apply again in February 1837^' (fig. 55). 

 By August 1837 he had developed a motor with a 6- 

 pound rotor, about half a foot across, that rotated at a 

 speed of 1,000 rpm and that could raise a 200-pound 

 weight at a speed of 1 foot per minute when driven by 

 three cells. Later in the year, he used this new ma- 

 chine to run a drill and turn a piece of hard wood 3 

 inches in diameter on his lathe. ^* Li an exhibition in 



»3 Thomas Davenport, "Specification of a Patent for the 

 Application of Electro Magnetism to the Propelling of Ma- 

 chinery," Journal of the Franklin Institute, 1837, vol. 20, pp. 340- 

 343. U.S. Patent 132, February 25, 1837. 



'< "Notice of the Electro-Magnetic Machine of Mr. Thomas 

 Davenport of Brandon, Near Rutland, Vermont," American 

 Journal of Science, 1837, vol. 32, appendix, pp. 1-8; aho Mechanics' 

 Magazine, London, 1837, vol. 27, pp. 159, 204-207, 404-405, 

 and letter from Thomas Davenport to editor, American Journal 

 of Science, 1838, vol. 33, appendix, pp. 1-2. 



264 



BULLETIN 228 : CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



