420 Scientific Intelligence. 
hydrogen chloride gas is disengaged in abundance at a red heat; 
and if the action be continued in presence of water vapor, a con- 
siderable proportion of the chloride will be decomposed, depend- 
ing on the amount of alumina in the kaolin. Bromides under 
these conditions evolve hydrogen bromide; but iodides evolve 
iodine, the hydrogen iodide being broken up by the heat. If the 
kaolin is anhydrous and the calcination is effected in a current of 
dry air, chlorine, bromine and iodine are evolved, but the action 
is much slower. By using kaolins free from carbonates, by mix- 
ing them thoroughly with the quantity of salt that they can com- 
pletely decompose and by carrying the mixture in half an hour to 
a cherry-red and maintaining it there for three-quarters of an 
hour in a current of steam, 97 per cent of the chloride may be 
decomposed, yielding hydrogen chloride. With absolutely dry 
materials, heated in dry air to a bright cherry-red, about one-half 
of the chlorine contained in the salts is obtained free.—Ann. 
Chim. Phys., V1, x, 145-170, Feb. 1887. G. F. B. 
3. On the Distribution in the Soil of the nitrifying organisms. 
—In a paper published some years ago, WARINGTON gave an ac- 
count of the experiments which he made at Rothamsted to ascer- 
tain to what depth the presence of the nitrifying organisms could 
be detected in the soil. From three series of experiments em- 
bracing 28 trials he concluded that “in our clay soils the nitrify- 
ing organism is not uniformly distributed much below 9 inches 
from the surface.” Subsequently, further experiments in this di- 
rection were made, essentially similar to the others except that 
rather more soil was placed in the solution to be nitrified and to 
this solution a decigram of gypsum was added to each liter. The 
results were now in many respects entirely different. Not only 
was the process of nitrification more speedy but soil from very 
considerable depths was found capable of starting it. Soil from 
a fallow plot had this property uniformly to a depth of 2 feet and 
in some cases to 3 and even 4 feet. Soil from a white clover plot 
was all effective down to 3 feet, and one sample at 4 feet and one 
at 6 feet were found to be so. The lucerne plot produced nitrifi- 
cation with all samples down to 4 feet and one sample at 6 feet 
was active. A third series of experiments was made a year later, 
to see if these results could be due to the contamination of the 
solutions in the field by soil-dust from the surface. But the re- 
sults confirmed. those already obtained. No failure to produce 
nitrification was observed in samples of soil down to and includ- 
ing a depth of two feet from the surface. At 3 feet only one 
sample out of eleven failed. At 6 feet one-half the trials failed ; 
and at 7 and 8 feet all failed. The failure in the earlier experi- 
ments was due the author thinks to the absence of gypsum from 
the test solutions. The final conclusion, therefore, is that the 
nitrifying organisms are practically confined to the surface soil ; 
for although they may occur at considerable depths in a loam or 
clay subsoil, they occur there in small quantity and in feeble 
condition.— JS. Chem. Soe., li, 118, Feb. 1887. G. F. B 
