48 KANSAS ACADEMY OF SCIENCE. 
Fifteen individual grains were analyzed, and their variation was from 1.72 per 
cent. to2.30. These figures show that, to make selection most effective, we must — 
be able to separate the desirable kernels from the less so, and not depend simply 
on selection of ears. Upon this problem we are still at work. It is evident that 
we cannot analyze our kernel, and plant it too, and that some physical test only 
is available. Our task is to find a usable physical property which varies with 
the per cent. of nitrogen. The specific gravity suggests itself as best adapted to 
our needs. Investigation of this point has not yet reached definite results. The 
differences in specific gravity are very slight, and since parallel determinations 
of the nitrogen in single kernels are impracticable, a large number of analyses 
will be necessary before a positive result can be expected. The determination of 
the specific gravity, while theoretically simple by means of a heavy solution and 
the Westphal balance, presents considerable difficulty because of the adherence 
of air to the grain with great tenacity, and because of the occurrence of cavities” 
within the kernels sometimes. 
Analysis of the several parts of the grain has shown that the germ is much 
the richest in nitrogen. Constituting about ten per cent. of the weight, it con- 
tains sixteen per cent. of the nitrogen. It also contains sixty-five per cent. of the 
oil. An increase in the size of the germ, therefore, will insure an increase in the 
percentage of the most valuable parts. Differences in the size of the germ are 
easily seen by simple sections through the kernels with a sharp pocket-knife, and 
ears can be selected showing a predominance of large germs. 
WATER PURIFICATION. 
BY W. TWEEDDALE, TOPEKA. 
Read before the Academy December 30, 1898. 
The character of the water-supply of a country is the determining element of 
its potential future, as regards its being the habitation of man, whether it be by 
the solitary pioneer or a community of individuals, as in ranch, village, town, or 
city like New York, with a population of millions. 
Modern sanitation requires that not only shall the quantity be abundant, but 
that the quality shall be suited to the uses to which it is to be applied. Medical 
science forbids that the cholera-infected water in the sacred tanks of India be 
longer used for dietetic purposes; and in the same line demands that, if water 
for potable purposes cannot be procured, provision be made to render it so by 
some system of purification. The necessity for this purification is due to the 
very solvent power of water acting on solid substances, such as clay, the presence 
of which ina state of suspension causes turbidity, together with the solvent power 
of gases in water acting chemically on inorganic earth salts, causing the property 
termed hardness and the fermentation (putrefactive decomposition) of organic 
substances, the presence of which in this state constitutes the nidus for the de- 
velopment of bacteria. 
In this country the purification of public water-supplies has been mainly re- 
stricted to the removal of visible impurities in suspension, including bacteria. 
This is sought to be done by filtration or by subsidence. There are two systems 
of filtration: Ist, sand filters, English system, as it is termed, with or without 
being allowed to deposit the coarser particles by sedimentation; and, 2d, the me- 
chanical filters, American system, combined with the use of a coagulant. 
Subsidence is the practice in cities whose sources of supply are the waters ob- 
