SCIENTIFIC SUMMARY. 
315 
Marlborough, of the appearance of the various species. So far as appears, it 
is only the observation of the date of first flowering that is required ; the 
advent of other phases of vegetable life is no doubt less capable of definite 
determination, but would seem to be desirable. Blank forms for the record 
of 11 Phenological Phenomena,” as the appearances of animals and plants 
are awkwardly styled, can be obtained of the Secretary of the Meteorological 
Society, 30, Great George Street, S.W., to whom also the said forms are to 
be returned at the end of each month. 
CHEMISTRY. 
The Mode of determining Glycerin and Succinic Acid in Wine. — M. Mau- 
mene has published a recent paper, which has been abstracted by the 
“ Chemical News ” (April 23) from “ Les Mondes.” It seems that the 
author holds that the quantity of these bodies, as produced by the fer- 
mentation of glucose simultaneously with alcohol, will be proportionate to 
the latter, and that the exact knowledge of their amount may thus indicate 
the quantity of extraneous alcohol added to wine. He prepares hydrated 
oxide of lead by decomposing a soluble salt of that metal with potash, and, 
after washing it well, suspends it in water. To half a litre of wine, con- 
centrated by evaporation to 335 c.c., he adds oxide of lead enough to cause- 
every trace of colour to disappear. A grey precipitate is formed. Filter,, 
wash the precipitate, and evaporate to dryness in the water-bath. Treat 
the evaporated residue with absolute alcohol, holding a little hydrated oxide 
of lead in suspension. Stir, leaving the mixture to stand for some hours, 
and filter. The liquid thus obtained is colourless. If submitted to a 
current of carbonic acid it grows turbid, but becomes clear again on 
filtration. It is dried at 110° C., and weighed as pure glycerin. To deter- 
mine succinic acid, treat a litre of wine with albumen, or raw hide, in 
sufficient quantity to remove all the tannin. Mix with hydrated oxide of 
lead (after concentration) till the colour is entirely removed, and preserve 
the filtrate for the determination of glycerin. The precipitate is kept for a 
long time in contact with boiling water, containing about 10 per cent, of 
nitrate of ammonia. The clear liquid, obtained on fresh filtration, con- 
tains all the succinic acid in the state of succinate of lead, besides other 
salts of the same base. It is treated with sulphuric (sulphurous) acid, and 
filtered again, when we have a perfectly colourless liquid containing free 
succinic acid. After having heated to expel the excess of sulphuric (sul- 
phurous ?) acid, the liquid is concentrated to about 100 c.c., and neutralised 
with ammonia. Heat sufficiently to expel any excess of ammonia, and add 
a few drops of ferric chloride, which has been previously kept for a long time 
in contact with sesquioxide of iron, so as to ensure the absence of free- 
hydrochloric acid. Finally, collect the deposit of succinate of iron which 
forms, wash it well, ignite, and weigh the residual sesquioxide. This 
weight, x 1*978, gives the quantity of succinic acid existing in the quantity 
of wine analysed. 
Hydrogen in the Metals. — It is stated by M. M. Troost and Hautefeuille- 
