SCIENTIFIC SUMMAET. 
91 
combined. He conducts the process in a graduated tube, and considers that 
the height of the deposit gives a fair, though rough, indication of the pro- 
portion of organic matter present. 
The Chemidry of the Tannic Acids. — Herr Hlasiwetz has published the 
second part of his memoir on the tannic acids, in which he treats of the tan- 
nic acids extracted from Jesuits’ bark and male-fern. When these acids are 
submitted to the action of dilute mineral acids they give rise to the produc- 
tion of sugar and of some other undetermined product of decomposition. 
Hence, from this point of view they behave in a manner similar to the 
Glucosides. — Vide Vlnstitut, Oct. 9. 
The new Laboratory at the Sorhonne. — This magnificent establishment, 
which is to be devoted to the pursuit of chemical investigation, seems to 
provide for the student’s wants on even a more liberal scale than its cele- 
brated rival at Berlin. Besides the various rooms for researches in chemistry, 
pur et simple, there are numberless apartments exclusively intended for in- 
vestigation in optics, electricity, mechanics, and so forth. Motive-power is 
provided for by a steam-engine of great force, which is connected by 
means of bands with wheels in the several laboratories. Again, besides the 
ordinary pipes carrying coal gas, there will be a series of pipes supplying 
oxygen from retorts kept constantly at work. Indeed, altogether the New 
Laboratory will be a species of Elysium for the chemical investigator. 
The Absorptive Action of Soils. — At the meeting of the Chemical Societ}" 
on November 7, a paper was read by Mr. Robert Warrington, jun., in which 
the author treated of the part taken by oxide of iron and alumina in the 
absorptive action which soils exhibit. Experimenting with the artificially 
prepared hydrates of alumina and ferric oxide, as well as with two samples 
of native soil containing widely different amounts of the same ingredient (or 
rather, oxide of iron and alumina ” 6-82 and 19 31 per cent, respectively), 
the author tried the effects of passing solutions of tricalcic phosphate, alka- 
line carbonates and sulphates, ammonium salts, &c., through them, for the 
purpose of ascertaining the rate and extent of absorption. Inasmuch as the 
calcareous constituents in the natural soils would have interfered with the 
actions which it was now intended to observe, these matters were first removed 
by digesting in weak acetic acid and thoroughly washing with water. The 
soil thus purified was left for several days in contact with a carbonic aqueous 
solution of the tricalcic phosphate, a current of carbonic acid gas being occa- 
sionally passed, and after the lapse of a week the ferruginous soil was found 
to have withdrawn 93‘8 per cent, of the phosphoric acid originally present 
in the solution, and only 49 per cent, of the lime. Hence the author believes 
that the ferric oxide and alumina may be considered to possess a special 
affinity for this mineral acid, and that all the phosphoric acid applied to land 
in the shape of manure must ultimately become converted into the phosphates 
of these bases. If the amount of iron be sufficiently large, all the phosphoric 
acid will be retained by preference in the form of ferric phosphate. The 
absorption power of soils for potassium salts was found to be much greater 
in the instances of the phosphate, sulphate, and carbonate, than with either the 
chloride or nitrate. The corresponding ammonium salts behaved in a similar 
manner. The author deduces from his experiments a general conclusion, to 
the effect that the absorptive action of soils, for the constituents named, i 
