286 The American Geologist. November, i89a 
the chemists of geometric isomerism, assume a configuration of 
the atoms, in accord with that of the molecule. 
The stimulating truth of the atomic constitution of the molecule, 
a great truth in elastic touch with all science, excites numerous 
hj'potheses, which, however profitable they may be, are to be 
stoutly held at a distance from the truth itself. Such are the hy- 
potheses of molecular aggregation into crystals and other mineral 
forms. Such are the biological theories of molecules polymerizing 
into cells, and of vitality as a chemical property of the molecule. 
Such are the questions of the nature of atoms, and the genesis of 
the elements as they are now known, questions on the border of 
metaphysics. Let all these be held distinct from the primary 
law of the atomic constitution of simple molecules in gaseous 
bodies, an essential principle in an exact science. The chemist 
should have the comfortable assurance, ever}' day, as he plies his 
balance of precision, that the atom-made molecules are there, in 
their several ratios of quantity, however many unsettled questions 
may lie around about them. Knowledge of molecular structure 
makes chemistry a science, nourishing to the reason, giving 
dominion over matter, for beneficence to life. 
Every chemical pursuit receives strength from every advance 
in the knowledge of the molecule. And to this knowledge, none 
the less, every chemical pursuit contributes. The analysis of a 
mineral, whether done for economic ends or not, may furnish a 
distinct contribution toward atomic valence. The further exami- 
nation of steel in the cables of a suspension bridge is liable to 
lead to unexpected evidence upon polymeric unions. Rothamsted 
farm, where ten years is not a long time for the holding of an 
experiment, yields to us a classic histor}' of the behavior of nitro- 
gen, a history from which we correct our theories. The analysis 
of butter for its substitutes has done something to set us right 
upon the structure of the glycerides. Clinical inspection of the 
functions of the living body fain finds a record of molecular 
transformations too difficult for the laboratory. The efliorts of 
pharmaceutical manufacture stimulate new orders of chemical 
combination. The revision of the pharmacopoeia every ten years 
points out a humiliating number of scattered errors in the pub- 
lished constants on which science depends. The duty of the 
engineer, in his scrutiny of the quality of lubricating oils, brings 
a more critical inquir}' into the laws of molecular movement. 
