13 



What Mr. Morse here describes as a " principle," the discovery of 

 which is unquestionably due to Professor Henry, is the law which first 

 made it possible to work the telegraphic machine invented by Mr. Morse, 

 and for the knowledge of which Mr. Morse was indebted to Professor 

 Henry, as is positively asserted by his associate. Dr. Gale. This gen- 

 tleman, in a letter, dated Washington, April 7, 1856, makes the following 

 conclusive statement : 



Washington, D. C, April 7, 185G. 

 Sir : In reply to your note of the 3d instant, respecting the Morse telegraph, 

 asking me to state definitely the condition of the invention when I first saw the 

 apparatus in the winter of 18o6, I answer : This apparatus was Morse's original 

 instrument, usually known as the type apparatus, in whi -h the types, set up iu 

 a composing stick, were run through a circuit breaker, and iu which the battery 

 was the cylinder battery, with a single pair of plates. This arrangement also 

 had another peculiarity, namely, it was the electro-magnet used by Moll, and 

 shown in drawings of the older works on that subject, having only a few turns of 

 wire in the coil which surrounded the poles or arms of the magnet. The sparse- 

 ness of the wires in the magnet coils and the use of the single cup battery were 

 to me, on the first look at the instrument, obvious marks of defect, and I accord- 

 ingly suggested to the Professor, without giving my reasons for so doing, that a 

 battery of many pairs should be substituted for that of a single pair, and that the 

 coil on each arm of the magnet should be increased to many hundred turns each ; 

 which experiment, if I remember aright, was made on the same day with a bat- 

 tery and wire on hand, furnished I believe by myself, and it was found that while 

 the original arrangement would only send the electric current through a few feet 

 of wire, say 15 to 40, the modified arrangement would send it through as many 

 hundred. Although 1 gave no reasons at the time to Professor Morse for the 

 suggestions I had proposed in modifying the arrangement of the machine, I did 

 60 afterwards, and referred in my explanations to the paper of Professor Henry, 

 in the 19th volume of the American Journal of Science, page 400 and onward. 

 It was to these suggestions of mine that Professor Morse alludes in his testimony 

 before the Circuit Court for the eastern district of Pennsylvania, in the trial of 

 B. B. French and others vs. Rogers and others. — See printed copy of Complain- 

 ant's Evidence, page 1G8, beginaing with the words "Early in 1836 I procured 

 40 feet of wire," &c., and page 169, where Professor Morse alludes to myself and 

 compensation for services rendered to him, &c. 



At the time I gave the suggestions above named, Professsor Morse was not 

 familiar with the then existing ttate of the science of electro-magnetism. Had 

 he been so, or had he read and appreciated the paper of Henry, the suggestions 

 made by me would naturally have occurred to his mind as they did to my own. 

 But the principal part of Alorse's great invention lay in the mechanical adapta- 

 tion of a power to produce motion, and to increase or relax at will. It was only 

 • necessary for him to know that such a power existed for him to adapt mechanism 

 to direct and control it 



My suggestions were made to Professor Morse from inferences drawn by read- 

 ing Professor Henry's paper above alluded to. Professor Morse professed great 

 surprise at the contents of the paper when I showed it to him, but especially at 

 the remarks on Dr. Barlow's results respecting telegraphing, which were new to 

 him, and he stated at the time that he was not aware that any one had even 

 conceived the idea of using the magnet for such purposes. 



With sentiments of esteem, I remain, yours truly, 



L. D. GALE. 

 Prof Jos. Henry, Secretary of the Smithsonian Institution. 



