80 WRITINGS OF JOSEPH HENRY. [1835 



CONTRIBUTIONS TO ELECTRICITY AND MAGNETISM. No. I. 



DESCRIPTION OF A GALVANIC BATTERY FOR PRODUCING ELEC- 

 TRICITY OF DIFFERENT INTENSITIES. 



(Transactions American Philosophical Society, n. s., vol. v, pp. 217-222.)* 

 Read January \&th, 1835.t 



The following account of a Galvanic Battery, constructed 

 under my direction for the Physical Department of the Col- 

 lege of New Jersey, is submitted to the American Philosoph- 

 ical Society, with the intention of referring to it in some 

 communications which I purpose making on the subject of 

 Electricity and Magnetism. It is hoped however that the 

 arrangement and details of the instrument, in themselves, 

 will be found to possess some interest, since they have been 

 adopted in most cases after several experiments and much 

 personal labor. 



The apparatus is intended to exhibit most of the phe- 

 nomena of Galvanism and all those of Electro-Magnetism, 

 on a large scale, with one battery. It was constructed to il- 

 lustrate the several facts of these branches of science to my 

 class, and also to be used as a convenient instrument of re- 

 search in all cases where no very great degree of intensity 

 is required. 



The several parts of this battery are not soldered together 

 forming one permanent galvanic arrangement, but are only 

 temporarily connected by means of movable conductors and 

 cups of mercury. The whole is constructed with reference 

 to the principle well understood of producing electricity 

 of greater or less intensity, by a change in the method of 

 uniting the several elements with each other. 



The apparatus consists of eighty-eight elements or pairs, 

 composed of plates of rolled zinc nearly one eighth of an 

 inch thick, nine inches wide, and twelve inches long, inserted 

 into copper cases open at top and bottom. Eleven of these 



*[The title-page of this volume bears date 1837.] 



t[The date given in the " Transactions " is January 14. This appears 

 from the Minutes to he a typographic error.] 



