Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 2, 1802).djvu/389

357&#93; GAL v. any two poini ■ liether raon i. distant, in a system of muscu- lar and nervous organs. The ex- mruunication may be considered as a complete circle di- vided into two parts, one of which, comprising the organs of the ani- mal under th • experiment, is ( the animal arc ; die other, which is formed b) the metals or gat lominated tatoryarc; and consists of more than on-. 1 ; piece, of various kinds. ide tii, effedts thus produced on the muscles, the impressions made on the organs of sense are equally remarkable. And as the experiments illustrating them may be easily r< peated, we shall specify some of the most interesting. For instance, it" a thin plate of zinc be placed on the upper surface of die . half crown, shilling, or silver tea-spoon, be laid on the lower surface of the tongue, and both metals after a short space of time be brought into contact, a peculiar sensation similar to taste, will be perceived at the moment i the mutual touch happens. If the silver be put beneath, and the zinc upon the tongue, the same sensation will arise, butin a weaker degree, resembling diluted ammo- niac, from which it in all proba- bility derives its origin. If a silver probe be introduced as far a > convenient into one of the nostrils, and then be brought into o mtact with a piece of zinc placed on the tongue, a sensation not un- like a strong dash of light will be produced in the corresponding eye, at the instant of contact. A simi- lar perception will result*, both at the moment of contact and at that of sej; aration, if one of the metals tx- applied as high as possible be- G A L [ 357 □ the gums and upper lip, and tin- other in a similar situation with the under-lip, or even under the ie. — Lastly, when a pr< rod of zinc, and another of silver, are introduced as far back as pos- ihc ropf of the mouth, the irritations produced by bringing the external ends into contact, are very powerful ; and dial caused by the zinc is similar in taste to toe sensation arising from its applica- tion to the tongue. No method has hitherto been ered, of applying theGalvanic influence in such a manner as to affect the senses of smell, hearing, and touch ; though several eminent philosophers have carefully inves- tigated the subject. Nor are the causes oi these phenomena clearly ascertained; Ga'lvani and some of his followers, supposing them to d pond on the electric fluid, while others attribute them to the influ- ence of various physical agei ey. In this state was G lv; ism, when in the year iSOO, Sign* r Volta, Professor of Natural Fiu- losophy, at Como, in nese, communicated to Sir Joseph Banks, a discovery of the vast accumulation of this power : it was accordingly presented to the Royal Sccieiy, fr< m the 2d part of whose Transactions, tor lbCO, we have selected the following ac- count. Sign. Volta's apparatus con- sists of a number of copper or sil- ver plates (which iast are prefer- able), tos eu.er v, ith an eouaJ num- ber of plateS composed of tin, or still better of zinc, and a similar number of pieces of card, leather, or woollen elotn, the last of v. hich substances appears to be the most suitable. These last should be v* ell soak< d in s ater saturated with A a 3 com-