34:3 



promotes its passage into the aorta. Thus he considers inspiration 

 as an auxiliary to the venous, and expiration to the arterial, circula- 

 tion ; the first acting like a sucking, and the latter like a forcing pump, 

 in aiding the power of the heart. On this principle he explains the 

 influence exerted on the circulation and on the action of the heart by 

 various modes of respiration, whether voluntary or involuntary, in 

 different circumstances. Laughter, crying, weeping, sobbing and 

 sighing, &c, he considers as efforts made with a view to effect certain 

 alterations in the quantity of blood in the lungs and heart, when the 

 circulation has been disturbed by mental emotions. 



6< Experimental Researches in Electricity." Tenth Series. By 

 Michael Faraday, Esq., F.R.S. D.C.L., &c. &c. 



This paper relates altogether to the practical construction and use 

 of the voltaic battery. Guided by the principles developed in former 

 series, the author concluded that in voltaic instruments in which the 

 copper surrounded the zinc, there was no occasion for insulation of 

 the contiguous coppers, provided they did not come into metallic 

 contact j and therefore in the construction of some new instruments 

 he interposed paper only between the coppers instead of the usual in- 

 sulating plate of porcelain or glass. The battery thus constructed is 

 essentially the same with Dr. Hare's ; and the author recommends 

 even his form of trough for the purpose of putting the acid on to, and 

 moving it from the plates. By attending to certain points described, 

 as many as 40 pairs of plates could be packed into a space not more 

 than 15 inches in length, and thus a very portable, and, at the same 

 time, powerful and convenient trough might be obtained. 



In comparing this form of trough with others, the author used acids 

 ,of constant strength, took note of their quantity, allowed them to 

 act in the troughs until the power of the apparatus had nearly ceased, 

 estimated the quantity of effect by his volta-electrometer, and then 

 estimated the quantity of zinc in the battery employed in producing 

 the effect by the results of an analysis of a given portion of the ex- 

 hausted charge. In this way it was easy to tell how much zinc was 

 dissolved from any one plate, or from all the plates, and to compare 

 it with the quantity of water decomposed in the volta-electrometer. 

 Thus, with a perfect battery of 40 pairs of plates, an equivalent of 

 water decomposed in the volta-electrometer would be the result of 

 the solution of an equivalent of zinc from each zinc plate, or forty- 

 equivalents in the whole 3 but with a battery not so perfect, a greater 

 proportion of zinc would be dissolved by the acid in the cells. 



When the new battery was thus compared with that of the ordi- 

 nary form, it was found to have greatly the advantage. Thus, with 

 40 pairs of plates, the former lost2 - 21 equivalents at each plate, 

 and the latter 3"54. With 20 pairs of plates, the former lost 3*7 per 

 plate, and the latter 5*5. With 10 pairs of plates, the former lost 

 6 76 per plate, and the latter 15*5. The author refers to two diffi- 

 culties still existing in the construction of the battery, but considers 

 its value so great as to deserve receiving that degree of attention, 

 by the application of which these difficulties may be removed. 



