SCIENTIFIC SUMMARY. 
87 
The Syrups of Low- class Wines. — These syrups are special saccharine liquids, 
analogous to the j uice of grapes, containing tannin, salts, &c., and colouring 
matters. It appears, says the “Revue de Chimie Scientifique,” No. 41, that 
they are to be mixed with the residue of the grapes after the first pressure and 
pressed again, so as to yield a further quantity of a liquid which may pass 
for wine. M. Mene thinks that by this system “ dangerous and gross falsi- 
fications ” may be prevented, which are a calamity to; the country and to 
society, because they interfere with, and injure, not merely health, but busi- 
ness and progress. 
Variation of the Quantity of Carbonic Acid according to the Weight of Atmo- 
sphere. — M. Truchot has published, in the u Comptes Rendus ” of Sept. 22, 
a series of observations which were made almost daily during July and 
August at Clermont Ferrand. The method consisted in passing the air into 
baryta- water previously titrated, then allowing deposition of the carbo- 
nate formed, then titrating anew the limpid supernatant liquor, a known 
quantity of which was separated with a pipette. The numbers obtained! 
show — (1) That the proportion of C0 2 is a little greater during the night, 
than during the day (as was previously observed by De Saussure and 
Boussingault). (2) That the proportion is not sensibly higher in the town 
than in the country. (3) That in the neighbourhood of plants with green 
leaves in full vegetation the proportion of C0 2 varies considerably according 
as these green parts are illuminated by the sun, or are in shade, or quite in 
darkness ; this agrees with a well-known fact in vegetable physiology. 
(4) That, on a general average, the proportion is 4*09 vols. per 10,000 vols. 
of air, which closely agrees with the numbers obtained by De Saussure 
(4T5), Thenard and Boussingault (4), and Yerver (4’2) ; but is much 
higher than those of German observers, Schulze (2’9), and Henneberg (3-2) 
at Rostock and Weende. To ascertain the influence of height, determina- 
tions were made simultaneously at Clermont Ferrand, 395 metres above the 
sea ; at the top of Puy de Dome, 1,446 metres ; and at the top of Lancy,. 
1,884 metres. The respective numbers were 3T3 vols. (per 10,000 of air) r 
2*03, and 1*72, showing a marked decrease with the height. 
The Coefficient of Expansion of Carbon Disulphide. — This has been deter- 
mined by Mr. J. B. Hannay, who lately (Nov. 20) read a paper on the 
subject before the Chemical Society. This paper contains the results of a 
numerous series of determinations of the specific gravity of carbon disulphide 
at small differences of temperature made in an apparatus of peculiar con- 
struction, so as to prevent evaporation, and to admit of the subsequent 
expansion of the liquid when adjusted at low temperatures. When the 
apparatus was carefully cleaned, the disulphide could be heated in it con- 
siderably above its boiling-point, thus affording a means of obtaining its 
specific gravity at comparatively high temperatures. The temperature cf 
the specific-gravity bulbs was adjusted by immersing them in water kept at 
a constant temperature by a modified form of Carmichaels apparatus. Two 
tables of the calculated and observed variation from 0° to 62° C. in the 
volume and specific gravity of the disulphide, the latter referred to water at 
4°, accompany the paper. From the results the author concludes that 
carbon disulphide expands equally for each equal increment of temperature, 
the number denoting the coefficient of expansion being 0001129, and that 
