38 



interview then terminated, and I have since had no further communication 

 with him on the subjeet. 



5. Please state whether or not you ever constructed any machine for 

 producing motion by magnetic attraction and repulsion ; if yea, what was 

 it, and what led to the making of it. 



Answer. — After developing the great magnetic power of the electro- 

 magnet as already described, the thought occurred to me that this power 

 might be applied to give motion to a machine. The simplest arrangement 

 which suggested itself to my mind Avas one already referred to, namely, 

 causing a movable bar, supported on a horizontal axis like a scale beam, 

 to be attracted and repelled by two permanent magnets. This could be 

 readily effected by transmitting through a coil of wire around the suspended 

 bar, a current of galvanism, first in one direction, and then in the opposite 

 direction, the alternations of the current being produced by dipping the 

 ends of wires projecting from the coils into cups of mercury connected 

 with batteries, one on either side. An account of this was published in 

 Silliman's Journal, for 1831, vol. xx., p. 340. It was the first successful 

 attempt to produce a mechanical motion which might apparently be 

 employed in the arts as a motive power. This little machine attracted 

 much attention at home and abroad, and various modifications of it were 

 made by myself and others. I never, however, regarded it as practically 

 applicable in the arts, because of the great expense of producing power 

 by this means, except, perhaps, in particular cases where expense of 

 power is of little consequence. 



6. Please look at the drawings of the Columbian Telegraph, now shown 

 you, marked G. W. B. and N. B. C, and certified by G. S. Hillard, 

 Commissioner. Describe generally the apparatus represented and its 

 mode of operation, and state in what respects, if any, it differs from the 

 telegraphic apparatus patented by Mr. Morse. 



Answer. — I have looked at the drawings, and I find, on examination, 

 that it will be impossible for me to give a definite answer to the question, 

 unless I have more time than is now at my disposal, and the means of 

 examining and comparing the operations of the machines. 



7. Please state, if you can, how many original experiments you have 

 made in the course of your investigations in electricity, magnetism, and 

 electro-magnetism. 



Answer. — The experiments I have mentioned in this deposition form 

 but a small part of my original investigations. Besides many that I made 

 ia Albany, which I have not mentioned, since my removal to Princeton, 



