412 



Scientific Intelligence. 



amount of gas which a battery is capable of yielding ; and at the Royal 

 Institution in the year 1840, I showed a voltameter constructed on this 

 principle, which yielded mixed gas from a battery of four square feet 

 surface, at the rate of 110 c. i. per minute. The voltameter used in 

 these experiments was one which M. Gassiot caused to be constructed 

 upon a suggestion of mine, and which consisted of five pairs of plates, 

 each exposing to the other eight square inches of surface. Any num- 

 ber of these plates could be thrown into action at a time, so that exclu- 

 ding the outward sides of the exterior electrodes, the sectional area of 

 the electrolyte would be 8. . 8+8 . . 16+8, and so on up to 72 square 

 inches. The diminution of the sectional area of the electrolyte in the 

 battery occasioned by the porous cells, was ascertained by first charg- 

 ing a given battery with sulphate of copper without any porous cell, as- 

 certaining the amount of decomposition per minute, and then placing 

 in the battery the porous cells, which had been previously soaked in the 

 same solution of copper, — again decomposing, and calculating from the 

 difference the diminution of area. The following is the table of ex- 



and which will in great part explain 



periments made with that view 

 itself: 



!f 



September 24/*, 25<A, 



26th, 1845. 



No. of Cells of 



N. A. Buttery 

 in series. 



Jo. united in 

 quantity. 



surface exposed 

 of Battery 

 each plate. 



1 

 1 



1 



id. 



Surface exposed 



of Electrodes in 



sq. inches. 



Quantity of Gas 



in c. i. per 

 minute. 



2 



8 

 8 



8 





8 



72 



72 



32 



8 



1 

 Wire 



A trace 

 id. 



67 



6 



5-2 

 2-8 

 0-9 



2 



4 



32 





72 



64 



56 

 48 

 40 

 32 

 24 

 16 

 8 



1 



Wire 



20-5 

 205 

 20-3 



20 



20 



19*4 



18-8 



16 



12 



35 

 1 



Remarks.— Battery in these experiments charged with nitric acid, sp. gr. 139, su p w 

 acid, 1-22, or l-f-4 water. 



Dr. Faraday remarked on the importance of this investigation, a ^ 

 its application to the principles of electro-telegraphic communication , 

 now that the discharging; current was to be made through the e f r{ ' 



8. On a new theory^of the Polarization of Light ; by Prof. i>ha - 

 lis, (Proc. Brit. Assoc, Allien., No. 1028.)— In this theory eiMr ^ ]{j 

 garded as a continuous fluid substance, and is treated mathema ic 

 on hydrodynamical principles. By means of a new general equ ^ 

 in hydrodynamics, which the author has discovered, he shows tna ^ 

 ament of the fluid may continue in agitation without lateral spre ^ v^ 

 and that motion may be propagated along it uniformly, provi e ^ 

 motion consist of vibrations partly longitudinal and partly trans 



