GALVANIC DISCOVERIES. 103 



he (hall be able to finiih it in lefs than two or three years. 

 When I left him he was going to publilh Tables of Galvanic Publishing 

 Affinity, including all the fubftances on which he has made ^ n " ^Jity. 

 experiments. Thefe tables will be of as much importance to 

 galvanifm as thofe of Bergman were to chemiftry : they will 

 fhow, though not yet in a complete manner, the order in which 

 fubftances follow each other with refpecl to exciting or re- 

 ceiving the galvanic aclidn. 



But to return to the experiments refpecling the charging of The galvanifed 

 , , ' ■ ' . . x n l • ■ " ft piece of metal 



metals. Mr. Ritter, alter having mown me his experiments h as two poles. 



on the different contraclibility of various mufcles, made me 



obferve, that the piece of gold galvanifed by communication 



exerts at once the adion of two metals, or of one constituent 



part of the pile; and that the half which was next the nega. 



tive pole while in the circle became pofitive, and the half 



toward the pofitive pole became negative. I was completely 



convinced of the reality of thefe different phenomena, fo 



important to phytic in general, and to phyfiology in par* 



ticular. 



Mr. Ritter having difcovered the method of galvanifing Golden needles 



metals, as iron is rendered magnetic, and having obferved that fV an j C d an 



galvanifed metals always exhibit two poles, as the magnetic 



needle does, had the curiofity to obferve the effect of golden 



needles charged with galvanifm and balanced on a pivot. 



To his furprife he perceived, that thefe needles had a certain have totftdl P 



.. ... . . . , r . . j . and variation, 



dip and variation, and that the angle ot variation, the quantity but different 

 of which I am forry I cannot recollect, was uniformly the * ro ™ the ma £* 

 fame in all his experiments. It differs however from that of " e ' * 

 the magnetic needlej and the pofitive pole always dips. 



VI. 



Improvement in applying the Points in Electrical Machines. By 

 Mr. G. J. Singer. 



To Mr. NICHOLSON. 



SIR, Princes Street, Sep. 19///, 1805, 



IN the ordinary conflruction of electrical machines, the col- 

 lecting points are fixed, and by the leaft. accidental motion are 

 liable to fcratch the glafs, to obviate this inconvenience, I 



place 



