236 
MISCELLANY. 
added six ounces of the balsam of Peru. Then melt a pound of pine- 
gum, and add spirits of turpentine until it is thin enough to strain, and 
finally, all the preceding preparations are mixed together. — Ibid, from 
Jour, de Phar. 
On a new Process for obtaining pure Chlorine Gas. By Profs. R. E. 
Rogers and W. B. Rogers. — This process is founded on the powerful 
oxidating action of chromic acid, especially when liberated in a solu- 
tion, and consists in causing a reaction between hydrochloric acid and 
this substance, in which the chlorine of the former is set free. Our 
mode of proceeding is as follows: — 
To 1 part of powdered bichromate of potash, in a small retort or 
flask, we add six parts of hydrochloric acid, of spec. grav. about 1.16, 
and apply a gentle lamp heat for a few seconds, so as to bring about a 
brisk reaction. The chlorine is now rapidly evolved, and continues to 
be disengaged as fast as is convenient, without requiring any further 
application of the lamp. 
Referring to the composition of the bichromate of potash and of 
hydrochloric acid, it will be seen that 1 equivalent of bichromate of 
potash and 7 of hydrochloric acid, arc capable of evolving 3 equivs. of 
chlorine, at ihe same time giving rise to 1 equiv. of the sesquichloride 
of chromium, 1 of the chloride of potassium, and 7 of w r ater. 
In order to ascertain how near we might approach to the equivalent 
quantity of chlorine above deduced, we resorted to the following 
method : — Knowing that a strong solution of chloride of sodium is 
much less absorbent of the gas than ordinary water, we prepared a 
quantity of saturated brine, through which we passed chlorine until the 
liquid appeared to be fully charged. With this we filled a tall gradua- 
ted vessel, designed to receive the gas, and a porcelain bowl, which 
served as a pneumatic trough, and having placed 4 grms. of the bichro- 
mate with an excess of hydrochloric acid in a small retort, we passed 
the gas as it was evolved through the chlorous saline solution into the 
narrow graduated jar. After urging the process until the action entirely 
ceased and no further gas escaped, we measured the resulting gas with 
the usual precautions at 60°. Its volume was found to be 54.5 cubic 
inches. On repeating the experiment with the same amount of bichro- 
mate and acid, and with the same brine, we obtained in the second 
trial 55.5 cubic inches, and in the third 56.2 cubic inches of the gas, 
the increase being evidently due to the diminished absorption arising 
from the more complete saturation of the liquid with chlorine. 
Taking 76.5 grs. as the weight of 100 cubic inches of chlorine at G0° 
F.,the volume due, to the entire decomposition of 4 grms. of bichro- 
mate of potash is 57.3 cubic inches. It thus appears that, with proper 
