234 Scientific Intelligence. 
of rupture in the more compact subaqueous deposits of clay 
an rl. 
IT am indebted to my son, L. J. LeConte, for the facts 
above recorded. He had the opportunity of carefully observ- 
ing the phenomena under consideration, in connection with the 
reconnaissiince of the Sacramento valley, in relation to the 
improvement of the navigation of the river as well as our great 
engineering problem of the disposal of the debris resulting 
from hydraulic mining. 
Of course every one is familiar with the cracks in mud or 
clay due to the shrinkage consequent upon drying; but, as 
far as I am aware, no one has called attention to the fact that 
they may be developed on so large a scale as to become an im- 
portant factor in the physical geology of past ages. 
SCIENTIPEG INTELLIGENCE. 
I. CHEMISTRY AND PuysiIcs. 
1. "On the Relation between the Optical and Thermal phenom- 
ena of Liquid Organic ,substances.—Briut has continued his re- 
searches on the connection between the physical properties of 
organic bodies and their chemical constitution, and in his last 
paper discusses the relation between the optical and the thermal 
phenomena observed in organic liquids. He finds: Ist, that pro- 
gressive oxidation has the same influence on the optical as on the 
1 
thermal properties; the refractive power, represented by et Es, 
diminishing as the amount of oxygen is increased, precisely a8 
the heat of combination diminishes. Removal of hydrogen, or its 
replacement by oxygen produces the same effect ; so that both the 
ab 
still less. 3d, in the homologous series of alcohols, acids and 
ethers, both the optical and the thermal constants increase with 
