May 17, 1912] 
Oswald Veblen, Princeton; George Friedrich Julius 
Arthur Auwers, Ph.D., Berlin; Wilhelm Ostwald, 
Se.D., LL.D., Leipzig; Magnus Gustaf Retzius, 
Stockholm. 
SaturDay, APRIL 20—MorNING SESSION 
President Keen in the chair 
Some Geochemical Statistics: FRANK W. CLARKE. 
The author first discussed the average composi- 
tion of the igneous rocks, and then compared them 
with rocks of sedimentary origin. From the 
amount of soda lost by the decomposition of the 
igneous rocks, and the amounts retained by the 
sedimentaries or leached into the ocean, he showed 
that about 78,000,000 cubic miles of the primitive 
crust of the earth had been decomposed, forming 
a mass of rock consisting of about 80 per cent. 
shales, 15 per cent. sandstones and 5 per cent. 
limestones. He next compared the rate at which 
river waters transport dissolved salts to the ocean, 
with the composition of the ocean itself, and from 
these data computed the probable age of the earth 
since the continents assumed their present form at 
something near 83,000,000 years. The saline mat- 
ter of the ocean alone amounts to about 5,000,000 
cubie miles, or enough to cover the entire surface 
of the United States with a solid mass a mile and 
three quarters thick. The rate at which sediments 
are being deposited in the ocean was also deter- 
mined, and found to be about 0.000027 inch an- 
nually. 
Some General Results of the Work of a Century 
on the Atomic Weights of the Chemical Ele- 
ments: GUSTAVUS D. HINRICHS. 
Absorption Spectra and the Solvate Theory of 
Solution (Illustrated): Harry C. JONES. 
A large number of lines of evidence have been 
brought to light in the laboratory of the author, 
all pointing to the conclusion that a dissolved 
substance combines with more or less of the solvent 
jn which it dissolves, about 7,000 solutions have 
now been studied with respect to their power to 
absorb light. It has been found that a given 
colored compound dissolved in different colorless 
solvents absorbs light very differently in the dif- 
ferent solvents. This is interpreted as being due 
to a combination of the different solvents with the 
dissolved substance, forming the different com- 
pounds which absorb light differently. The bear- 
ing of this work on the nature of solution is im- 
portant, and solution is the most important condi- 
tion known to man from the standpoint of natural 
science in general. 
SCIENCE 
791 
Matter in the pure homogeneous condition does 
not enter into chemical reaction. It become active 
chemically only when dissolved. Chemistry, biol- 
ogy and geology owe their existence to matter in 
the dissolved state, and any light thrown on the 
nature of solution is of importance for the natural 
sciences in general. 
The theory of solution hitherto held has been 
found to be insufficient, not applying to the very 
solutions that give us natural science. 
In dealing with solutions we must always take 
into account the part of the solvent combined with 
the dissolved substance. 
The Classification of Carbon Compounds: Marston 
T. BogErt. 
The subject is considered primarily from the 
standpoint of classification for purposes of in- 
struction in organic chemistry. The various ways 
in which carbon compounds have been classified 
from time to time are traced historically, from 
the earliest period to the present, and the author 
expresses himself in favor at the present day of a 
classification based on chemical structure, grouping 
together all compounds of essentially similar fune- 
tion. Thus, all hydrocarbons, saturated and un- 
saturated, acyclic and cyclic, should be considered 
together, all simple halogen derivatives, and so 
forth. The author has used this method with his 
students at Columbia University for the past ten 
years and has found it very satisfactory. 
An Autocollimating Mounting for a Concave 
Grating (Illustrated) : HorAcE CLARK RICHARDS. 
Thermal Relations of Solutions: Winu1aM F. 
MAGIE. 
The heat capacity of electrolytes dissolved in 
water is related to the temperature change of the 
heat of dilution. Experiments to demonstrate this 
were described and it was pointed out that the 
heat of dilution is a difference between two quan- 
tities of heat—one evolved in an amount propor- 
tional to the absolute temperature—the other ab- 
sorbed in an amount independent of the tempera- 
ture. One of these quantities is proportional to 
the dissociation which occurs on dilution and meas- 
ures the energy lost by the solute as its ions com- 
bine with water. The other involves as a part of 
its value the heat absorbed by the dissociation. 
A formula for the relations of the osmotic pres- 
sure to the temperature was proposed, from which 
the heat of dilution can be deduced. It was shown 
for solutions of common salt that the constants of 
this equation can be calculated from the freezing 
points and the boiling points of the solution, and 
