Polytechnic Association Proceedings. 1003 



describing one of Ritchie's coils, giving sparks six and a half inches 

 long. He also describes the mode iu which the secoudary coil is 

 made up of a succession of conical layers. 



Mr. Ritchie's reputation soon became deservedly celebrated, and 

 orders fol* his coils were received from Europe. Mr. Gassiot, of 

 Loudon, describes one in the London Ed. Phil. Mag. for May, 

 1858, page 446. This coil gave sparks of the enormous length of 

 twelve and a quarter inches by accurate measurement, and Mr. 

 Gassiot said he was confident it would give fifteen inches, but was 

 afraid to force it too much, lest the insulation should be penetrated. 

 Mr. Gassiot speaks of the coil as made up in sections, and that 

 "the method of winding had been before suggested by Poggen- 

 dorfi*." In this he was in error. Poggendorff suggested " dividiuir 

 the coils lengthwise into several sections," and, to use his own lan- 

 guage, " each section being wound up in the usual manner " of 

 superposed layers. Mr. Ritchie's coil was, indeed, made of sec- 

 tions, but there were as many as spires of wire in the whole length 

 of the instrument, and each of these was womid up, not in the 

 usual way, but as a flat spiral. A sectional arrangement, which 

 necessitated a new mode of winding and an entire change in the con- 

 struction and power of the coil, is a very wide departure from Pog- 

 geudorif 's plan, or rather Messrs. Bright's plan. Thus we find that 

 the commencement and perfection of the induction coil, which we 

 shall hereafter characterize as the electrostatic coil, must be 

 accredited as American inventions. Of this we shall speak further 

 in another chapter. After Mr. Ritchie's invention was known in 

 Europe, a new impulse was given to the subject, and coils of 

 nearly equal power were brought out by Ruhmkorlf and other 

 instrument makers. A communication iu the Franklin Journal of 

 1862, vol. 73, page 58, shows the manner in which M. Ruhmkorflf 

 became acquainted with Mr. Ritchie's improvements, and his pre- 

 vious refusal to accept a challenge to furnish a coil equal in length 

 of spark to Mr. Ritchie's. In the application of Fizeau's condenser, 

 we recognize a discovery and invention of high value and interest, 

 which will abide as a monument of his learning and genius. 

 Latterly, we have heard of coils giving sparks " two feet long," 

 from coils eighty miles in length. (iVbacZ's Inductonum, London, 

 1866, page 42.)* Adjourned. 



• Wo have annexed illustrations of the principal apparatus alluded to in Prof. Page's 

 article, several of which were not described by reference to the engravings. 



