Additional Notes. 453 



bahlHty, be concluded, that it is to this chemical action that 

 the ekcitatioii of the Galvanic influence is owing.'* 



Those who wish to see a more detailed account of the 

 hisrory of Galvanism, especially of the numerous and very 

 interesting experiments and discoveries made in this branch of 

 philosopiu% in the years 1801 and 1802, wiii do well to con- 

 sult the Pliilos. Trons. for 1801, 'TiLi^ocvCs Pliilus: Mag. 

 and Nicpiolson'^ Journal of Natural Philosophif. 



Magnetism. 



. Jriificial Magnets, p. 33. 



" As every piece of iron which was made magnetical by 

 the touch of a magnet became itself a magnet, many at- 

 tempts were made to improve these artificiai magnets, but 

 without much success, till Servingdcn Savery, Esq. of 

 Great-Bntain, m/ade tiiem of hardened steel bars, which 

 were so powerful, that one of them, weighing three pounds 

 averdupois, would hft another of the same weight. 



" After this Dr. Gowin Knight made very successful 

 experiments on this subject, which, though lie kept liis me- 

 thod secret, seems to have excited others to turn their atten- 

 tion to magnetism. About this time the Rev. Mr. Michel 

 invented an equally efficacious and more expeditious way of 

 making strong artificial magnets, which he published in the 

 end of the year 1 730, in which he explained his method of 

 ■what he called the Double Tout'h, and wiiic^h, since Dr. 

 Knight's method has been known, appears to be somewhat 

 different from it. 



" 7"his method of rendering bars of hardened steel mag- 

 netical, consists in holding vertically two or more magnetic 

 bars nearly parallel to each other, with their opposite poles 

 very near each other (but, nevertheless, separated to a smnll 

 distance) : these are to be slided over a line of bars, laid 

 horizontally, a few times backward and forward. 



" What Mr. Michel proposed by this method was, to in- 

 clude a very small portion of the horizontal bars intended to 

 be made magnetical, between the joint ft)rccs of two or 

 more bars already magnetical, and, by sliding them from 

 end to end, every part of tlie line of bars became succes- 

 sively included ; and thus bars, ix)ssessed of a very small de- 

 gree of magnetism to begin with, would, in a very few 



