DISCOUIISE Ol' W. 15. TAYLOR. 221 



five pounds; of the armature, about one and one-fourth pound ; and 

 with a single galvanic pair whose acting zinc surface was about 

 eleven square feet, the electro- magnet supported about 50 i)ounds. 

 With cautious additions, the load could be increased to 75 pounds. 

 An additional galvanic pair of about six square feet was api^licd 

 without increasmg the power of the magnet. Another horse-shoe 

 about twelve and a half inches in height, formed of a rod two 

 and one-fourth inches in diameter, was prepared by Professor Moll, 

 with a brass wire, one-eighth of an incli thick, wound around 

 it in forty-four coils; the weight of the whole being about twenty- 

 six pounds. With the galvanic element of eleven square feet, 

 this magnet lifted 135 pounds. The largest load this magnet was 

 afterward made to support was 154 pounds.* 



As soon as the account of Moll's magnet reached this country, 

 (late in October, or early in November,) Henry — who had obtained 

 and had publicly exhibited nearly two years previously, considera- 

 bly higher results, and who realized that there was at least one very 

 important difference of construction between his own magnet and 

 that of the Dutch savant, felt it a duty at once to publish the details 

 of his own researches, in a more public form. He accordingly 

 proceeded in the latter part of November, 1830, to write out a 

 description of his former experiments and results, which he for- 

 warded to Silliman's American Journal of Science, (then published 

 only quarterly,) in time for insertion in the forthcoming number of 

 that journal, for January, 1831; causing a copy of Professor 

 Moll's paper, taken from Brewster's Edinburgh Journal of Science 

 for October 1830, to be inserted in the same number. At the con- 

 clusion of liis own article he remarks: "The only effect Professor 

 Moll's paper has had over these investigations, has been to hasten 

 their publication : the principle on which they were instituted was 

 known to us nearly two years since, and at that time exhibited to 

 the Albany Institute." 



Comparing now Moll's results with Henry's, — we find that 

 Henry's magnet of November or December, 1829, (a half-inch bar 



* Brewster's Edinburgh Jour. Set. Oct. 1830, vol. lil. n. s. pp. 209-214. An account of 

 Moll's magnet is also given In the Annates de Chimie el de Physique, 1832, vol. i« 

 pp. 324-328. 



