SCIENTIFIC SUMMARY. 
317 
presence of even a small quantity of this metal. The surface of the tinning 
must he carefully cleansed before applying the nitric acid, and the acid 
should not penetrate to the iron or copper which forms the body of the- 
vessel, as the reaction might thus be complicated.” 
A ncn-arsenical Green Paint is a matter of some importance, but not 
easily obtained. It seems likely, however, that it has been produced by 
Signor A. Casali. This Italian chemist states ( u Gazzet. Chim. Italiano,”" 
Anno IV., Fasc. 9) : “ That the existing chrome greens, such as Guignet’s 
green (hydrated sesquioxide of chrome), called also emerald green, and 
Pannetier’s green; green ultramarine (anhydrous chromic oxide), Leune 
and Castelhaz’s green (hydrated chromic oxide), Arnaudon’s green (chromic 
metaphosphate ?), Matthieu Plessy’s green (phosphate), leave little to be 
desired in point of beauty, and are free from injurious properties, but are 
too expensive to compete with the arsenical greens. He proposes in their 
stead to calcine strongly an intimate mixture of 1 part of bichromate of 
potash and 3 parts of baked gypsum, of the variety commonly known as 
scagliola. The result is a grass-green mass, which, on boiling with water, or 
mixing with dilute hydrochloric acid, leaves a fine powder of an intense 
and beautiful green, and possessing a very high colouring power. 
The Detection of Common Alcohol in Wood-spirit has been recently carried 
out by M. Berthelot (see u Comptes Bendus,” April 26, 187*5). The 
process consists in mixing the suspected liquid with double its volume of 
concentrated sulphuric acid. In these conditions methylic alcohol yields 
gaseous methylic ether, entirely absorbable by water or concentrated sul- 
phuric acid, whilst ordinary alcohol produces ethylen, a gas almost insoluble 
in water, and concentrated sulphuric acid, but which may be recognised and 
determined by causing it to be absorbed in bromine. On operating with 
the precautions customary in gaseous analysis, the presence of common 
alcohol may be detected in wood-spirit, even when the proportion does not 
exceed 1 or 2 per cent. Aceton and the normal impurities of wood-spirit 
may yield, under these circumstances, carbonic acid and carbonic oxide, 
but not ethylen. 
The Detection of Amy lie Alcohol in Spirits of Wine. — This process, which 
is just the reverse of that previously described, is given in an Italian che- 
mical journal (see also the “ Chemical News,” May, 1875) by Dr. C. 
Betelli. It is as follows : — Dilute 5 c.c. of the suspected alcohol with 6 or 
7 volumes of water. Add 15 or 20 drops of chloroform, shake strongly, and 
leave at rest. The deposit of chloroform is collected, and allowed to 
evaporate spontaneously, when the amylic alcohol is left as a residue, and 
may be recognised by its well-known odour, its reaction with sulphuric 
acid, &c. 
The Gases evolved from Apples. — An examination of these has been made 
by Herr Bender, who has published the results in the “ Berlin Chem. 
Ges ” (viii. 112). The fruit, cut in pieces, was placed in water free from 
air contained in a flask furnished with a delivery-tube. On raising the 
temperature to 60°, the gas began to come off, and at 100° the evolution 
was rapid. Four moderately-sized apples afforded about 100 c.c. of gas. 
Upon eudiometric analysis this gas — great care having been taken to exclude 
the air — was proved to consist of 59*37 per cent, of nitrogen, and 40*20 per 
