8G 
rOrULAR SCIENCE REVIEW. 
whicli turns of a dirty green colour on tlie addition of a solution of per- 
chlorido of iron from the formation of oxyphenate of iron. Animal and 
vegetable fibres are dyed by the mixture of an ash-gi’ey colour of gTeat 
solidity. ]\r. Lefort’s process is as follows : The fibres are steeped in a 
solution of perchloride of iron for several hours, and when sufficiently 
drained, transferred to a vessel of filtered tar-water containing one of vege- 
table tar to ten of water heated to 60° or 80°. After several hours’ mace- 
ration they are withdrawn, washed with water and afterwards with soap, to 
remove the aromatic and resinous principles. — Chemical Neivs, Oct. 23. 
The Chemical Constitidion of Uric Acid. — In a note communicated to the 
Munich Academy of Sciences, Ilerr Strecher shows that uric acid may be 
regarded as a combination of glycocol and cyanuric acid (or 3 molecules of 
cyanic acid), just as hippuric acid may be regarded as a combination of 
benzoic acid and glycocol j for when it is heated for some time to 170° with 
concentrated hydrochloric acid, or, preferably, with a cold saturated solu- 
tion of hydriodic acid, it yields, after removal of the acid by oxide of lead, a 
considerable quantity of glycocol, together with carbonic acid and ammo- 
nia. — Vlnstitut, Oct. 28. 
Artificial Production of Tartaric Acid. — Along with his note on Vric 
Acid, Herr Strecker communicated to the Munich Academy another, on a 
new mode of forming tartaric acid. This consists in boiling for some time 
with dilute hydrochloric acid a mixture of glyoxal and prussic acid. The 
tartaric ac-id produced is precipitated from the solution by lactate of lime, 
and then obtained in the usual manner. IleiT Strecker has not yet studied 
its action on polaiised light. He considers its formation to be due to the 
union of glyoxal, prussic acid, and water, with the liberation of ammonia. — 
L'LiKtitut, Oct. 28. 
Phenomena of Combustion 'under Pressure. — M. II. Deville, in a lecture to 
the French Academy (Nov. 30), explains the fact established by Frankland, 
that the temperature of combustion of a gas is raised by making it burn under 
strong pressure by his theory of “dissociation.” When hydrogen burns in 
oxygen, only half the gas ever enters into combination in the hottest part 
of the flame, because the tension of dissociation resists it j and this is the 
reason why the temperature only reaches to 2,800° instead of 6,000°, the 
theoretical maximum temperature. By increasing the pressure on the gas, 
the influence of this tension of dissociation is lessened. 
Analysis of the Ashes of a Diseased Oranye Tree. — The orange plantations 
along the south-eastern coast of Spain, and in the adjacent Balearic Isles, 
having been visited with a severe epidemic, the rapid progi’ess of which 
rendered it of great commercial importance to the people there. Professor 
Bunsen, on a visit to tlie Baleaiic Isles, obtained specimens of the roots, 
stems, brandies, and fruit of the diseased trees. Mr. T. E. Thorpe has 
mailo analyses of the ashes of these part.s, and communicated his results to 
the Chemical Society. Comparing these results with those of analyses 
made f-omo years ago by Me.ssrs. Bowney and How of the ashes of liealthy 
St. Michael orange trees, tlie comparison of the two series of results shows 
a great dillerence between them ; but, then, so would a comparison of the 
results of analyses of the ashes of specimens of any species of plant in a 
healthy condition, but grown under different circumstances of soil, season. See. 
