146 Faraday's Researches j

subdivision of this series of Researches which contains the ;
account of the volta-electrometer (439, etc.).

521. In the next place, I also consider the law as established \
with respect to muriatic acid by the experiments and reasoning j
already advanced, when speaking of that substance, in the
subdivision respecting primary and secondary results (493, etc.).

522. I consider the law as established also with regard to j
hydriodic acid by the experiments and considerations already j
advanced in the preceding division of this series of Researches j
(502, 503). j

523. Without speaking with the same confidence, yet from j
the experiments described, and many others not described, \
relating to hydro-fluoric, hydro-cyanic, ferro-cyanic, and sulpho-
cyanic acids (505, 506, 507), and from the close analogy which j
holds between these bodies and the hydracids of chlorine, i
iodine, bromine, etc., I consider these also as coming under !
subjection to the law, and assisting to prove its truth.

524. In the preceding cases, except the first, the water is
believed to be. inactive; but to avoid any ambiguity arising

from its presence, I sought for substances from which ?

it should be absent altogether; and, taking advantage j

of the law of conduction already developed (116, etc.), j

I soon found abundance, amongst which -pro to chloride \

of tin was first subjected to decomposition in the j

following manner. A piece of platina wire had one \

extremity coiled up into a small knob, and, having i

been carefully weighed, was sealed hermetically into a 1

piece of bottle-glass tube, so that the knob should be j

at the bottom of the tube within (fig. 28). The tube \

was suspended by a piece of platina wire, so that the j

heat of a spirit-lamp could be applied to it. Recently j

fused protochloride of tin was introduced in sufficient j

quantity to occupy, when melted, about one half of the <

lg' ' tube; the wire of the tube was connected with a j

volta-electrometer (446), which was itself connected with the I
negative end of a voltaic battery; and a platina wire con-
nected with the positive end of the same battery was dipped " j

into the fused chloride in the tube; being however so bent, j

that it could not by any shake of the hand or apparatus touch j

the negative electrode at the bottom of the vessel. The whole \

arrangement is delineated in fig. 29. j

525. Under these circumstances the chloride of tin was j
decomposed: the chlorine evolved at the positive electrode ] similar use for electricity.