PROCEEDINGS. 
511 
nre, pure and simple, to cause a re-orientation of the axes of two crystal 
fragments, even if it could perfectly weld them together; nor would we 
expect pressure without heat to impart the ability to complete the fusion 
of a lump of barium sulphate in sodium carbonate, even after the reaction 
had been well started by heat. Under these extremely complex condi¬ 
tions it is difficult to generalize. A welding together is not only theoret¬ 
ically hut practically possible between two chemically clean surfaces that 
fit, hut any operation which requires an increase of freedom of the mole¬ 
cules would scarcely be assisted by pressure. Cohesion and adhesion I 
believe to be identical, and molecular rather than molar. 
The bearing of these ideas, if good, upon geological phenomena is some¬ 
what thus : By the action of pressure and time a sandstone or such mate¬ 
rial might be rendered compact and coherent, and even continuous, the 
most plastic constituent yielding most, and the most viscous retaining 
their shape most perfectly. Some’constituents might even appear to 
have been fused and filled in between the rest; certain crystallographic 
changes might take place, but more than the slightest chemical effect of 
the constituents upon each other is not to be expected. The case be¬ 
comes infinitely complex, and the subject for conjecture only, if the tem¬ 
perature is high. An indisputable fact in this connection is that many 
more experiments are needed, and such that each effect can be ascribed 
to its proper cause, and not, as at present, causes and effects treated col¬ 
lectively. 
See, also, Science, vol. 11, p. 152; also , Am. J. Sci., vol. 34 (3. s.), 
p. 277; also, ibid., vol. 36 (3. s.), p. 59. 
317th Meeting. March 31, 1388. 
The President in the chair. 
Thirty-five members and guests present. 
Mr. C. V. Riley presented a communication on Some Recent 
Entomological Matters of International Concern. [This paper 
has been published by the U. S. Department of Agriculture in 
the Periodical Bulletin of the Division of Entomology for No¬ 
vember, 1888, vol. 1, No. 5, p. 126.] 
Mr. H. A. Hazen presented a paper on “ Two Balloon Voy¬ 
ages.” 
[Abstract.] 
It was shown that with modern safety appliances ballooning was by no 
means the dangerous pastime it was generally thought to be. Most of the 
fatal accidents were due to the use of hot-air balloons or to carelessness on 
the part of the aeronaut. The first voyage was from St. Louis, in the 
“World” balloon, on June lf>, 1887—a balloon of 160,000 cubic feet 
