288 EB. W. Hilgard—Silt analysis of Soils and Clays. 
two, viz.: salicylic acid and phenol, may be considered the 
legitimate products of the action of potassic hydroxide upon 
potassic sulphosalicylate. 
It remained to study the corresponding reaction with the 
second variety of potassic sulphosalicylate. The experiment 
ormed in exactly the same manner as in the first case ; 
and all the phenomena observed were but repetitions of those 
already described. Salicylic acid and phenol were the only 
products. The salicylic acid was not analyzed, as its properties 
were a sufficient guarantee of its identity. The phenol was 
detected, as in the former case, by means of Landolt’s reaction. 
If we consider the phenol as a secondary product, formed by 
the splitting up of salicylic acid under the influence of heat, 
we thus see that the effect of the action of potassic hydroxide 
in the cases under consideration is simply to cause a substitu- 
tion of the SO?0H group by H. Similar instances are men- 
whether any connection can be traced between the positions 
of the substituting groups, and the occurrence of this retro- 
grade substitution. 
Williams Oollege, Mass., August, 1873. 
Arr. XXXL—On the Silt Analysis of Soils and Clays ; by Eué. 
W. Hitearp, State Geologist of Mississippi. 
(Read at the Portland Meeting of the Am. Assoc. Adv. Sci., August, 1873.) 
so il 
It makes a material difference whether the grains of sand 
contained in a soil or clay are prevalently half a millimeter 2 
diameter, or the tenth or twentieth part of that amount. _ and 
(or more properly silt) of the latter size is by no means 1M 
pable; and yet a soil containing 50 per cent of this substance 
might be exceedingly “heavy,” while it would be “ ie 
the sand grains approached 05™™ diameter. And it wou 
