30 
specimens, and on the little knowledge that we have thus.far 
had regarding the fossil insects of America. 
Pror. D. 8. MARTIN said that he considered this series of 
specimens one of the most interesting that had been brought 
before the Lyceum for along time. It is to be hoped, and 
expected, that with the great number and extent of our Ter- 
tiary lake-deposits in the far West, from which we are obtain- 
ing such wonderful richness of both mammalian and 
vegetable fossils, there will be. found, by suitable care and 
search, a correspondingly ample harvest in fossil entomology. 
This beautiful set, which Mr. Mead has exhibited, seems a 
foretaste of what lies in store for us, when these Miocene lake- 
beds shall have been thoroughly explored by geologists 
familiar with insects. 
He also called attention to the article in the last number of 
the Geological Magazine, on fossil Lepidoptera, in which 
several new species are described, and some interesting sug- 
gestions presented as to their geographical relations as com- 
pared with existing types. 
Mr. JAMES HyatrT called attention to some peculiar 
barometric phenomena observed by him, in connection with 
the action of wind in mountainous districts. He had been 
wont to carry with him, while traveling up and down on the 
Hudson River railroad, a very reliable aneroid barometer, 
and had been led to notice its curious variations in passing 
from station to station. These variations at first seemed 
wholly inexplicable; but they were soon found to follow a 
very simple law, in relation to the ranges of hights traversed 
by the railroad. With a north wind the barometer stood 
highest on the northern side of the Highlands, and with a 
south wind, on the southern side. This result seems, there- 
fore, to be due to a condensation or compression of the air, 
when strong currents strike against ranges of mountains or 
hills. 
With a north-east wind, again, the barometer stands 
higher at Newburgh, at the base of the hights, on the west- 
ern side of the river, than it does at Fishkill, on the eastern 
