JANUARY 26, 1912] 
harmony with theirs. In this point of 
view, he came a century and a half too 
soon. Such a proof, if offered at the pres- 
ent day, would be accepted as conclusive. 
The final isolation of the element would 
now be considered a matter of mere rou- 
tine, that could be assigned to a beginner 
in research, as the basis of his dissertation 
for the degree of doctor of philosophy. 
Finally, the clouds of the phlogistie theory 
soon began to darken the sky of the science, 
and before long the spread of this remark- 
able notion, diligently fostered by Stahl, 
who had been born nine years before the 
appearance of Mayow’s work, enveloped 
chemistry and the whole chemical world in 
an impenetrable fog. Since the believers 
in phlogiston started always with one ab- 
surd idea as the major premise, namely, 
that, in combustion and oxidation, some 
kind of matter left the burning or rusting 
material, the more rigorous the logie of the 
subsequent steps in the reasoning, the more 
certain was the attainment of uniformly 
false conclusions. The inveterate phlogis- 
tian, and everybody down to the time of 
Lavoisier, not excluding Priestley and 
Scheele, was forthwith an inveterate phlo- 
gistian, saw in simple, almost modern 
modes of thought, like those of Mayow, 
only the sheerest nonsense. If we all stood 
habitually upon our heads, naturally any 
one caught persisting in a tendency to 
view the universe in the normal way 
would be instantly adjudged insane. For 
these various reasons, Mayow’s work was 
first neglected and then forgotten. 
The story of Mayow suggests some addi- 
tional conditions which determine the 
recognition of a discoverer, and the accept- 
ance of his discovery. How often in the 
history of science has a dominating but 
conservative personality diverted attention 
from younger or less prominent men, or at 
the least, by hostile criticism, delayed the 
SCIENCE 
123 
acceptance of their ideas. The discoverer 
who occupies a conspicuous social position 
is, often, more readily detected. Then 
again, for the dealing of strict justice, the 
consequences may be almost as unfortunate 
when the discoverer is a century ahead of 
his time, like Mayow, as when he is three 
years late, like Scheele. And, finally, an 
intellectual plague like the phlogistie the- 
ory may be epidemic. An infection runs 
until a milder generation of the infecting 
organism is gradually evolved, or until the 
presence of the organism results in physi- 
ological changes which automatically give 
rise to substances that destroy it. Lavoi- 
sier was fortunate in arriving upon the 
scene when the disease was ready to loosen 
its hold. It was not that his fundamental 
experiments, upon the subject of air and 
oxygen, were new—the same conclusions 
could have been reached by putting to- 
gether the work of his predecessors and 
contemporaries. It was largely because of 
his personality, and because he arrived at 
the psychological moment. 
I have prefaced my address in this way, 
in order to furnish a setting for its subject. 
He lived from 1711 to 1765. He thus was 
educated, did his life-work, and died in the 
most virulent period of the phlogistic epi- 
demic. Heat, light and weight were then 
forms of matter, yet, when he notices them 
at all, he combats these views, and makes 
experiments to disprove them. In a day 
when the jargon of the phlogistian was 
the only language of polite intercourse 
amongst chemists, he speaks and writes the 
language of modern chemistry—of the 
most modern chemistry, for he was a phys- 
ical chemist. Needless to say, he lived at a 
time far removed from the psychological 
moment for a man holding such a view- 
point. Naturally, credit for his discov- 
eries, and they were many, has all been 
distributed amongst others. It is quite 
