MURIATIC AND OXYMURIATIC ACIDS. 45 



I repeated the experiment in a vessel capable of containing a smaller «•*»*'• 

 , ./-.,... r ..with the»auie 



not more than 1400 grains of quicksilver, (about '41 of a cubic resu | t . 



inch,) the neck of which being only one-fifth of an inch in dia- 

 meter, was better calculated to show any minute change in the 

 volume of the gas. On removing the stopper, however, no 

 change of volume was apparent. The hydrogen erolved, in- 

 stead of being more than in the former experiment, equalled 

 in bulk only 20 grains of mercury. The production of oxy- 

 nmriatic acid was sufficiently evinced by its effect in tarnishing 

 some very small globules of quicksilver, which adhered to the 

 inside of the vessel ; but- the minuteness of the quantity frus- 

 trated an attempt to measure it. From subsequent expert* 

 ments on similar quantities of gas, confined in the same appa- 

 ratus, it appeared, that the electrization in this last instance, 

 had been continued much longer than was necessary ; and that 

 an equal effect was produced by one-eighth the number of elec- 

 trical discharges. 



In this way of making the experiment, the greatest propor- The hydrogea 



tion of hydrogen gas obtainable from muriatic acid, amounted evolved when 

 i iiiii-i.. , ., mercury is not 



only to about .^th, while, b/ electrization over quicksilver, present, i« 



tV, or t ! t was generally evolved. It was evident, then, that 1 * 70th ; blU d 

 1 ■ ' * D J ' ' present, 



the mercury had considerable influence over the results ; and i-l5th,or 



I found, by experiments with tubes of different diameters, " e ' ir!y five „. 



■ times as much, 

 that the larger the surface of the mercury exposed to the gas, 



the more rapid and complete was the change. Its action was 



greatly accelerated, also, by causing the electric discharge to 



strike from the conducting wire, sealed into the tube, to the 



mercury, which was probably thus raised into vapour; for in 



some instances, the whole of the inner surface of the glass 



was coated with sublimed calomel. 



The only way in which the mercury appeared to me likely The mercury 



to be efficient in this case, was by removing the oxymuriatic f PP ears to a<t 



. J ■ - J bv removing 



acid as fast as it was formed ; for I have never found any the oxyrauna- 



mixture of this gas in the results of experiments on muriatic J. ic aoi< * ** 



acid, when carried on over quicksilver. Upon any theory of 

 , . . c . . . % J J and prevent- 



the constitution of muriatic acid, it may be expected that when, ingthe repro- 



in a mixture of that acid gas with hydrogen and oxymuriatic d,,ction of 



. , .; *"*;■' . . common mu- 



acid gasses, the two latter come to bear a certain proportion to Hatic acid, 



the former, they will be brought within the sphere of mutual when t . he ot >'" 



agency, and will reproduce muriatic acid. Thii point appears, became* abua. 



from daat 1 



