28 University Geological Survey of Kansas. 
As sea water contains calcium carbonate, which is appreciably 
alkaline, and as it is in contact with the great oceans of atmos- 
phere above, it naturally absorbs the gases contained therein. 
Dittmar’ found that a liter of sea water would take up, at zero 
degrees C., 15.60 cc. of nitrogen and 8.18 cc. of oxygen, while at 
thirty degrees the proportions were 8.36 cc. of oxygen and 4.17 
ec. of nitrogen. Buchanan® found the amount of carbon dioxid 
in surface-waters to be at twenty to twenty-five degrees C. from 
.0466 grams per liter to .0268. The carbon dioxid is mostly 
united with sodium, although a small amount is united with 
calcium. 
RAIN WATER. 
The rain, which has been evaporated from the surface of the 
earth, which floats over our heads in clouds, is condensed and 
again waters the earth, is the original material from which 
mineral water is made. As it answers as a vehicle for dissolv- 
ing and transferring the mineral substances, its characteristics 
and composition should be first discussed. As the rain falls 
through the air it not only takes up the dust and floating par- 
ticles, which in cities and manufacturing districts are liable to 
be abundant, but it absorbs certain gases. ‘The per cent. of 
these gases, by volume, according to Baumert,‘ is, of nitrogen, 
64.47; of oxygen, 33.76; of carbon dioxid, 1.77. We find nor- 
mally about three parts of carbon dioxid in 10,000 parts of 
the atmosphere, and the carbon-dioxid gas being very soluble 
in water, the rain as it descends is found to contain fifty times 
as much as the same volume of air would contain. 
The newly discovered gases argon and helium are probably 
also present in rain water. Nitric or nitrous acid, uniting with 
ammonia, will be found in considerable quantity, and in the 
vicinity of towns and manufacturing centers hydrogen sulfid 
and sulfuric acid, and even such a solid substance as sodium 
chlorid (common salt) is lable to be present in rain water, 
especially in the vicinity of the ocean. Interesting experiments 
6. Proc. R.S., vol. 24. 
7, Ann. Chem. Pharm. LXXX, VIII, p. 17. 
