280 Progress in Science. (April, 
studying by physicists, especially as regards development of heat and 
electricity. 
In some researches on change in pitch of tones through movement of the 
source of sound, and determination, by this means of the velocity of sound, 
Dr. Schiingel experimented with two tuning forks, No. 1 giving 512, and No. 2 
508 vibrations in a second, Sounded together they gave four beats in a 
second. But suppose No. 2 moved towards the observer (situated beside 
No. 1), its quantity of vibrations would be increased and the number of beats 
diminished. Dr. Schiingel sought to measure—(z) the time in which a certain 
number of successive beats was audible; and (2) the velocity of the moved 
fork. His apparatus (which was eleGrical) may be briefly described :—A 
seconds pendulum at each swing closed a circuit, which, through a relay, 
caused a series of dots to be marked on a telegraph strip at intervals cor- 
responding to seconds. By pressing a key another battery circuit could be 
closed, which had two effects: part of the current went to the relay, and pro- 
duced a line in the telegraph paper so long as the key was held down ; but the 
greater part went through an eleétro-magnet, which attracted an armature at 
one end of a lever, having at its other end a roller rotated by a cord from a 
fly-wheel. The roller was thus pressed against the edge of a disc, which, thus 
set in motion, wound in, by a cord about its axis, a little wagon bearing the 
tuning fork (No. 2) with its case towards the observer. The method, with 
some suggested modifications, is commended to the attention of physicists 
for an accurate determination of the velocity of sound. 
TECHNOLOGY. 
Count Sokolnicki, a proprietor of vineyards at Medoc, states that a chemist, 
so-called, is selling to the wine-forgers of the Gironde a liquid of which a few 
drops suffice to coloura wine. An cenanthic liquor, simulating the bouquet 
of Medocs, is sold openly at Bordeaux. A solution of sugar is allowed to 
ferment on the pressed grapes, the colour and the flavour are added, and with 
these materials wines of the best growths are counterfeited. 
For the manufacture of permanent beer M. Pasteur recommends the use of 
a pure yeast,—the mode of preparing which he does not describe,—free from 
vibriones, baéteria, Mycoderma aceti, &c. With such yeast, the process of 
fermentation can be carried on in the absence of air, or in the presence only 
of limited quantities of pure air. Beers thus made can, he declares, be pre- 
served for an indefinite length of time, even at temperatures of 20° to 25° C. 
M. Paul has effected an improvement in photo-lithography. He produces a 
positive image on paper covered with a layer of albumen mixed with a con- 
centrated solution of bichromate of potash. After a sufficient insolation 
under the negative, the paper is covered with lithographic ink, and then im- 
mersed in cold water to dissolve the unaltered albumen. 
As a test for the colouring matter of wines, M. de Cherville gives the fol- 
lowing process:—Pour into a glass a small quantity of the wine under 
examination, and dissolve in it a morsel of potassa. If there is no deposit, 
and if the wine takes a greenish tint, it has not been artificially coloured. If 
a violet deposit has been formed, the wine has been coloured with elderberries 
or mulberries; if the deposit is red, beet-root or peach-wood has been used; 
and if violet-red, logwood. If the sediment is violet-blue, privet berries have 
been employed; and if a bright violet, litmus. 
A paper ‘*On Coloured Tapers,” by Mr. James MacFarlane, Assistant to 
the Professor of Chemistry, St. Andrews, was recently read before the 
Chemical Section of the Glasgow Philosophical Society. The author detailed 
a series of experiments which he had prosecuted for the purpose of deter- 
mining the nature of the colouring matter in the green and red wax tapers. 
He distinétly ascertained that the former owed their colour to the presence of 
Scheele’s green (arsenite of copper). Their average weight was 2 grms., and 
the average time occupied in burning was seventeen minutes. Guided by the 
Rp tS 
