314 
POPULAR SCIENCE REVIEW. 
protection of tlie plates of steam-boilers and of iron ships, the use of iron 
saucepans in place of tinned vessels, iron for many domestic purposes re- 
placing the more costly copper ; and we may, moreover, look forward to the 
time when leaden pipes for the conveyance of water will be entirely super- 
seded. Again, there is every reason to suppose that this new process 
possesses many advantages over “ galvanizing” applied to materials made 
of iron. 
Succinic Acid in the Juice of the TJnripe Grape. — During an examination 
of the juice of the unripe grape, conducted by Brunner and Brandenburg, 
with the hope of detecting as constituents glyoxylic acid and desoxalic acid, 
these observers recognized the presence in considerable quantity of succinic 
acid. The expressed juice of fruit, gathered in the middle of June, formed 
the material. After treatment with lime carbonate, and the removal of 
protein compounds by raising the liquid to the boiling point, the filtered 
liquid was concentrated and further purified with animal charcoal ; a crys- 
talline body was at length obtained, which proved on analysis to be calcium 
succinate. The acids sought for were not met with, and this failure to 
detect them is ascribed to the possibility of the grape having reached to an 
advanced stage of its development; the authors therefore intend to repeat 
their experiments with fruit at a still earlier period immediately after 
flowering. If they succeed in proving glyoxylic acid to be a normal con- 
stituent cf the plant, a conception of the gradual conversion of carbonic acid 
into the vegetable acids under the reducing action of light may be arrived at 
— a metamorphosis in harmony with reactions which can be performed in 
the laboratory. The acids referred to, as well as others met with in 
vegetable tissues, might then be regarded as successively derived from a 
hypothetical carbonic hydrate by the following stages of reduction : — 
2(CH 2 0 3 ) + H 2 = C 2 H 2 0 4 + 2H 2 0 
oxalic acid 
c 2 h 2 o 4 +h 2 
C 2 H 2 0 3 +- H 2 
2(C 2 H 2 0 3 ) + H 2 
c 4 h 6 o 6+ h 2 
c 4 h 6 0 5 +h 2 
= C 2 H 2 0 3 + H 2 0 
glyoxylic acid 
= C 2 H 4 0 3 
glycollic acid 
- c 4 h 6 o 6 
tartaric acid 
= c 4 h 6 o 5+ h 2 o 
malic acid 
= c 4 h 6 o 4 +h 2 o 
succinic acid 
Oxalic acid is present in the leaves of the vine, according to Neubauer, who 
found it to be abundantly present, as well as some malic acid, in the wines 
of inferior vintages like that of 1871. Malic acid is not met with in wines 
of good vintage, although it occurs plentifully in the leaf of the vine at a 
certain stage of its growth. Neubauer also found succinic acid in the spring 
sap of the vine, and Gorup-Besanez detected the presence of glycollic acid 
and malic acid in the leaves of the Virginian creeper. — Zeitschrift fur 
analytische Chemie , 1877, xvi., 246. 
Nucite. — Tanret and Villiers have isolated and analysed a crystallizable sugar 
which occurs in the leaf of the walnut. It crystallizes in clinorhombic prisms 
