Sdenll/lc NewJi Recounts of Boob, &e, 5«7 



Lettir from Mr. Davy, Supertntendant of the Pneumatic Irtjlituthti, contairmg Notices nn- 



cerning Galvanifm, 



To Mr. NICHOLSON. 



SIR, 



In purfuing my enquiries concerning the produflion of galvanic influence during me- 

 tallic oxidation, I have found that many of the difEcultly oxidable metals may be made to 

 a£t as Voltean combinations, by being connedted in pairs in the common order with fluids 

 capable of oxydating one of the alternate metals. 



Ten filver plates attached to thin gold wires, and arranged in glaflTes containing diluted 

 nitric acid, produced when their agency was applied in the ufual mode, a ftrong cauftic 

 fenfatlon on the tongue, and efFe£ted, though feebly, the ufual changes in water. 



Twenty pieces of copper in contafl: with Clver wires, when connefled with weak folu- 

 tions of nitrate of mercury a£ted powerfully, and that for a great length of time, i. e. till 

 almofl: all the mercury was precipitated on the copper. The influence produced fenfiblc 

 fliocks. Whan it was paiTed through water by means of gold wires, oxygen was given out 

 at the place of the copper, and hydrogen at the place of the filver. Whereas in the com- 

 bination with filver and gold, the oxygen was produced at the place of the filver, and the 

 hydrogen at that of the gold. 



The agency of galvanifm upon inorganic bodies appears to be Cmilar under all its dif- 

 ferent modes of excitement. I have found that the gafes evolved from water by the aftion 

 of feries in which the oxidating fluid media are acids, or metallic folutions, do not difler 

 in kind or properties from thofe produced by that of combinations in which the fluid media 

 are conftituted by common water. 



I have lately made many experiments on the fingle oxidating circles of Afli, and on the 

 influence of thofe circles on galvanic animal irritation. Thefe experiments will at fome 

 time be made public ; they go far towards proving not only that the circles of Afli are go- 

 verned by the fame laws as the pile of Volta ; but llkewlfe that there exifts in living mat- 

 ter galvanic afllon independent of all influence generated by metallic oxidation. I have 

 produced the phsenomena of tafte and mufcular irritation by means of metals, in cafes 

 when they were apparently incapable of undergoing chemical change. 



I am, SIR, 



with refped your's, 



Dowry Square, Hotwelhy HUMPHRY DAVY, 



Jan, 23, 1801. 



A new 



