84 
rOPULAR SCIENCE REVIEW. 
The Fermentation of Glycet'ine . — M. Bechamp, who alleges that chalk 
contains organisms still alive, and which have lived since the chalk period, 
states that Herr Redtenbacher has been trying the effect of these in ferment- 
ing glycerine, and Mr. Bechamp has presented an account of his experi- 
ments to the French Academy. The following mixture was made : — Pure 
glycerine, 250 grms. ; chalk, from Sens, full of well and lively-moving 
microzymas; hashed mutton, quite fresh, and previously washed with cold 
water, 30 grms. ; cold water, 3,000 c.c. This mixture was kept at a tempe- 
rature of from 35° to 40° for several months. The chief results obtained by 
the author are, that propionic, butyric, caproic, and valeric acids are formed 
most abundantly : among the gaseous products, carbonic acid, hydrogen, 
and nitrogen are found as result of this fermentation. 
Chemistry and Geology. — At the meeting of the Royal Physical Society 
of Edinburgh on November 24, Dr. Stevenson Macadam devoted his 
opening address, as president, to the above subjects, in their relation to each 
other. He asserted very strongly that geological phenomena — as pointed 
out often by Mr. David Forbes — cannot be interpreted without the aid of 
chemistry. 
Ill Health of Dr. Anderson. — We regret to learn from the reports of the 
Highland and Agricultural Society that Dr. Anderson, the chemist to the 
Society, has been compelled through ill health to give up work for a 
while. It is satisfactory, however, to find that both the Society and the 
"University of Glasgow have given him leave of absence. 
Piperinic Acid and its Products of Oxidation are the subjects of a paper 
presented recently to the Gottingen Society of Sciences by Herr Fittig. 
Herr Fittig went into many details, and gave an account of the products of 
oxidation of piperinic acid, of piperonylic acid, of the action of nitric acid 
on these compounds, and of the relation of piperinic acid with bromine. 
What the illuminating Power of Gas should be. — There are many of our 
readers who are interested in the practical chemical question, 11 What is 
good gas ? ” which the Chemical News asks in a recent issue. Giving 
abstract of a paper by Herr Schilling in the Journal fur Gasbeleuchtung, the 
Chemical Neivs states as follows : — A good and suitable gas for artificial 
illuminating ought to possess the following qualities: — (1) The gas ought 
to possess a normal illuminating power. The exact determination of the 
value of the normal illuminating power can only be obtained when the gas 
made from various qualities of coal, and manufactured according to rational 
principles, is compared, under exactly identical conditions, with the normal 
standard candle. Any gas which, by a combustion of five cubic feet per 
hour, exhibits a light equal to fifteen spermaceti candles, may be considered 
a gas of good illuminating power. (2) The gas should be absolutely free 
from sulphuretted hydrogen. (3) The pressure of the gas at the works and 
in the leading mains should, as a minimum, amount to from 08 to TO of the 
water-pressure gauge. 
Chloride of Gold in Crystals. — M. Debray publishes a fact of some interest 
as regards common chloride of gold. It is known that by heat this sub- 
stance is first changed into chlorine, and the protochloride, and that then 
this product changes into chlorine and metallic gold. M. Debray, however, 
finds that if thin leaves of gold are heated in a current of chlorine to 200° 
