DISCOURSE OF W. B. 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 pounds. 

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

 An additional galvanic pair of about six square feet was applied 

 without increasing 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 inch 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 Silli man'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 his 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. Sci. Oct. 1830, vol. iii. n. s. pp. 209-214. An account of 

 MOLL'S magnet is also given in the Annales de Chimie et de Physique, 1832, vol. L. 

 pp. 324-328. 



