THE EFFECTS OF CARBONIC ACID. 
203 
time indefinitely. After giving an outline of his mode of 
treating still liquor, Mr. Weldon described at considerable 
length the details of the process, both as to quantities, mate- 
rials employed and obtained, and the nature of the chemical 
compounds formed at different stages of the process. As 
explained by Prof. Roscoe, the principle upon which the pro- 
cess depends is that, although when alone the lower oxides of 
manganese cannot be oxidised by air and steam under the 
ordinary pressure to the state of dioxide, yet this is possible 
when one molecule of lime is present to each molecule of 
oxide of manganese. The manganous oxide is precipitated 
from the still liquors with the above excess of lime, and by 
the action of steam and air on this, a black powder, consisting 
of manganese dioxide and lime, or calcium manganit (Mn0 2 
Ca O), is formed. This compound is again capable of gene- 
rating chlorine from hydrochloric acid, and thus the chlorine 
process is made continuous with a working loss of only 2^ per 
cent, of manganese. 
A short discussion followed the reading of this paper, 
in the course of which Mr. Gossage stated that his expe- 
riments on the improvement of the chlorine process had 
extended over thirty-five years, and he was glad Mr. Weldon’s 
efforts had been attended with such a large measure of 
success. 
THE EEEECTS OF CARBONIC ACID. 
At the meeting of the British Association, Dr. B. W. 
Richardson read a paper on some “New Physiological 
Researches on the Effects of Carbonic Acid,” and in the 
course of an interesting communication he explained that the 
observations he had made were new, in that they related to 
the direct action of carbonic acid on animal and vegetable 
fluids, and they were interesting equally to the zoologist and 
botanist as to the anatomist. He first demonstrated from a 
specimen the result of subjecting a vegetable alkaline infusion 
to the action of carbonic acid under pressure. The result was 
a thick fluid substance which resembled the fluid which 
exudes as gum from some trees. When this fluid was gently 
dried it became a semi-solid substance, which yielded elastic 
fibres, and somewhat resembled caoutchouc. This observation 
had led the author to study the effect of carbonic acid on 
albumen, serum of blood, blood itself, bronchial secretion, and 
other organic fluids. When the serum of blood was thus 
