Chemical Science. — Prescott. 287 
There is not time to mention the many professions and pursuits 
of men ivho contribute toward the principles of ckemintry and hold 
a share therein. If it be the part of pure science to find the law 
of action in nature, it is the part of applied science both to con- 
tribute facts and to put theory to the larger proof. In the words 
of one who has placed industry in the greatest of its debts to 
philosophic research, W. H. Perkin, "There is no chasm between 
pure and applied science, they do not even stand side by side, 
but are linked together." So in all branches ol' chemistry, 
whether it be termed applied or not, the best workers are the most 
strongly bound as one, in their dependence upon what is known 
of the structure of the molecule. 
Studies of structure were never before so inviting. In this 
direction and in that especial opportunities appear. Moreover 
the actual worker here and there breaks into unexpected paths of 
promise. Certainly the sugar group is presenting to the chem- 
ist an open way from simple alcohols on through to the cell sub- 
stances of the vegetable world. And nothing anywhere could be 
more suggestive than the extremely simple unions of nitrogen 
lately discovered. They are likely to elucidate Unkings of this 
element in great classes of carbon compounds, all significant in 
general chemistry. Then certain comparative studies have new 
attractions. As halogens have been upon trial side by side with 
each other, so for instance, silicon must be put through its paces 
with carbon, and phosphorus with nitrogen. Presently, also, the 
limits of molecular mass, in polymers and in unions with water, 
are to be nearer approached from the chemical side, as well as 
from the side of physics, in that attractive but perplexing border 
ground between affinity and the states of aggregation. 
Such is the extent and such the diversity of chemical labor at 
present that every man must put limits to the range of his study. 
The members of a society or section of chemistr}-, coming to- 
gether to hear each other's researches, are better able, for the 
most part, to listen for instruction than for criticism. Still less 
prepared for hasty judgment are those who do not come together 
in societies at all. Even men of eminent learning must omit large 
parts of the subject, if it be permitted to speak of chemistry as 
a single subject. These considerations admonish us to be liberal. 
When metallurgical chemistry cultivates skepticism as to the 
work upon atomic closed chains, it is a culture not the most lib- 
