TRANSACTIONS OF THE SECTIONS. 77 



When, therefore, the dissimilar metals were employed as pole.?, the decomposition 

 of the water was not the mean of tliat producible by silver and by zinc, viz. 30, but 

 30 + 22 when the two forces acted in the same direction, and 30 — 23 when they 

 acted against one another. 



On a Powerful Galvanic Battery. By the Rev. H. Highxox, M.A. 



The following combination forms a cheap and simple galvanic battery, witli no 

 fumes or other inconveniences. The negative plate is carbon packed iu a porous 

 cell with precipitated sulphur, peroxide of manganese, and granulated carbon, tilled 

 lip with dilute acid. Sulphuric is the best. For the positive plate, zinc is placed in 

 a solution of caustic potash or soda. 



The author stated that the potential is about 2-G or 2-7 volts, and nearly 50 per cent, 

 higher than a Grove battery, and that one cell will abstract magnesium from its salts. 

 The internal resistance is rather large. If a solution of common salt be used for tlie 

 positive, the potential is about 10 per cent, higher than a Grove ; and with dilute 

 sulphuric acid in the positive part of the cell it is about the same as a Grove. In 

 the last case there is no occasion for the sulphur in the negative. The internal 

 resistance of this last form is small ; in the second form not great. 



On tiie effect iijyon Meteoric Iron, as regards the capaliillttj of being forged, of 

 previous heating to redness or ivhiteness in vacuo, i^y Professor J. W. Mallet, 

 Uaiversitij of Virginia. 



Three specimens were exhibited of meteoric iron from Augusta Co., Virginia. 

 Of these, the first had been cut from the original mass by a planing-machine, and 

 without further preparation had been forged into a tolerably perfect blade for a 

 paper-knife. The second had been heated to strong redness iu a poi'celain tube 

 rendered vacuous by a Sprengel's pump (for the purpose of examining the occluded 

 gases), and had then been with much difficulty forged into a blade ot similar kind, 

 in which cracks and ilaws were visible. 



The third had been heated in lilce manner in vacuo, but to a white heat ; and this 

 specimen, it was found, could not be forged at all, crumbling under the hammer 

 when re-heated. 



The conceivable causes of this difference were briefly discussed, such as the nrore 

 or less complete removal of the occluded gases, changed state of combination of 

 the phosphorus (and sulphur), and melting out of phosphide of iron, leaving the 

 iron porous. 



On the Fusion of Metallic Arsenic. 

 By Professor J. W. Mallet, University of Virginia. 



Experiments on this subject made by Mr. Dunuington and Mr. Adger (students 

 in the Laboratory of the University of Virginia), under the author's direction, were 

 described. 



These experiments had been undertaken in view of the generally repeated state- 

 ment that arsenic cannot be fused, but passes directly from the solid into the 

 vaporous state, and that an attempt to secure increased pressure by using a sealed 

 tube only results in bursting the tul3e. The statement by Laudolt * (given apparently 

 without further details), that by using a glass tube enclosed in one of iron, the metal 

 heated for some time to low redness under pressure may be melted into globules, was 

 noticed only after the experiments to be mentioned had been made, 



* Verliandl. d. niederrixein. Gesellscb.aft vom 4. August 1859, quoted in Will's Jahres- 

 bericht for 1859, p. 182. 



1S72. 7 



