HENRY AND THE TELEGRAPH. 281 



at once assumed (after a few oscillations) its equatorial position transverse 

 to the magnetic meridian. Such was the character of demonstration by 

 "Which the new Professor was accustomed to make visible to his classes 

 the principles of electro-magnetism. And it is safe to say that in sim- 

 plicity, efficiency, and conspicuous distinctness, such apparatus for the 

 lecture-room was far superior to any of the kind then existing. 



The details of this early contribution to electrical science were set 

 forth in a communication read by Henry before the Albany Institute 

 October 10, 1827, " On some modifications of the electro-magnetic api)a- 

 ratus." In this paper he remarks : 



" Mr. Sturgeon, of Woolwich, who has been perhaps the most success- 

 ful in these improvements, has shown that a strong galvanic i^ower is 

 not essentially necessary even to exhibit the experiments on the largest 

 scale. . . . Mr. Sturgeon's suite of apparatus, though superior to any 

 other as far as it goes, does not however form a complete set ; as indeed 

 it is plain that his principle of strong magnets cannot be introduced 

 into every article required, and particularly into those iiitended to ex- 

 hibit the action of the earth's magnetism on a galvanic current, or the 

 operation of two conjunctive wires on each other. To form therefore a 

 set of instruments on a large scale that will illustrate all the facts be- 

 longing to this science, with the least expense of galvanism, evidently 

 requires some additional modification of the api^aratus, and particularly 

 in those cases in which powerful magnets cannot be applied. And such 

 a modification appears to me to be obviously pointed out in the con- 

 struction of Professor Schweigger's galvanic 'multiplier'; the principles 

 of this instrument being directly applicable to all the experiments in 

 which Mr. Sturgeon's improvement fails to be useful."* 



Should any one be disposed to conclude that this simj)le extension of 

 Schweigger's multiple coil was unimportant and unmeritorious, the ready 

 answer occurs, that talented and skillful electricians, laboring to attain 

 the result, had for six years failed to make such an extension. Kor was 

 the result by any means made antecedently assured by Schweigger's 

 success with the galvanometer. If Sturgeon's improvement of econo- 

 mizing the battery size and consumption, by increasing the magnet 

 factor (in those few cases where available), was well deserving of reward? 

 surely Henry's improvement of a far greater economy, by increasing 

 the circuit factor (entirely neglected by Sturgeon), deserv^ed a still higher 

 applause. 



In a subsequent communication to Silliman's Journal, Henry remarks 

 on the results announced in October, 1827 : " Shortly after the publica- 

 tion mentioned, several other applications of the coil, besides those de- 

 scribed in that paper, were made in order to increase the size of electro- 

 magnetic apparatus, and to diminish the necessary galvanic power. The 

 most interesting of these was its application to a development of mag- 

 netism in soft iron, much more extensive than to my knowledge had been 



* Transactions of tl\e Albany Institute, vol. i, pp. 22, 23. 



