244 
conceivable directions at exceedingly high 
rates of speed; moreover, the atoms com- 
posing the different chemical elements are 
of determinate weights corresponding to 
their equivalents of combination ; these mi- 
nute particles attract each other with vary- 
ing degrees of strength and unite in simple 
ratios to form larger particles called mole- 
cules ; agglomerations of these molecules 
constitute masses, visible to the eye and 
subject to the laws of mechanics. 
Faith in this purely intellectual concep- 
tion has enabled men of genius to refer to 
it the explanation of many facts, and the 
hypotheses resulting have developed into 
laws of prime importance in chemical phi- 
losophy ; Dalton discovered facts in the 
union of chemical bodies whose interpreta- 
tion he found in the doctrine of atoms ; 
Humboldt and Gay-Lussac reinforced the 
Daltonian laws by their labors on the ra- 
tios in which the volumes of gases combine; 
Avogadro, by purely physical researches 
established the relation between the volumes 
of gases and the number of their constituent 
molecules; and Gerhardt, working in the 
field of organic chemistry, observed the 
bearing of these discoveries on chemical phi- 
losophy and, by clearly establishing the dis- 
tinction between atom and molecule, gave 
to the atomic theory its modern aspects. 
Faith in this theory has made it possible 
to devise a scheme of notation that in spite 
of its defects has proved of great utility in 
promoting the advancement of chemistry ; 
the multitudinous problems of  stoichio- 
metry ,the modern theories of solution and 
of electrolysis, the doctrines of isomerism 
and of stereo-chemistry are achievements of 
the intellect and of the reason based upon a 
belief in an imaginary condition of matter. 
To crown the whole, Newlands, the English- 
man, originated, Meyer, the German, and 
Mendeléeff, the Russian, brought to a high 
state of perfection, the Periodic law which 
has given to chemistry that prophetic power, 
SCIENCE. 
(N.S. Vou. XIII. No. 320. 
long regarded as the peculiar dignity of its 
sister science, astronomy. 
Quite apart from these abstract prin- 
ciples, based upon a belief in the atomic con- 
stitution of matter, is the practical side of 
the question, of which the analytical chem- 
ist avails himself in determining the value 
of substances submitted to him; on the re- 
sults of his figures thousands of dollars may 
change hands in the manufacturing, mining 
and commercial world. A ship-load of ma- 
terial is bought and sold on the result of the 
analysis of a sample conducted by a chem- 
ist, who bases his procedure on the supposed 
numerical relations of the invisible, in- 
tangible, immeasurable particles he calls 
atoms and in his calculations he relies on 
the constants determined by others, in 
whom he has confidence, and the accuracy 
of which constants he has to accept on 
faith. Reliance on the dicta and data of 
investigators whose very names may be un- 
known lies at the very foundation of phys- 
ical science, and without this faith in au- 
thority the structure would fall to the 
ground; not the blind faith in authority of 
the unreasoning kind that prevailed in the 
middle ages, but a rational belief in the con- 
current testimony of individuals who have 
recorded the results of their experiments 
and observations, and whose statements 
can be verified. 
This faith in the fundamental principles 
of physical science persists notwithstand- 
ing it encounters insurmountable difficul- 
ties. Many problems defy the efforts of 
materialistic philosophers to solve them; 
the origin of matter and of motion; the 
initial source of energy as well as the re- 
lation of gravitation to other forces; the 
positive nature of the interstellar ether 
imagined as a vehicle for the transmission 
of light, not to mention proofs of its exist- 
ence; the true inwardness of actinism, of 
Rontgenism, and of the rays named after 
Becquerel; the ultimate identity in es- 
