262 
chemistry was undertaken, and two years 
were spent largely in mastering the prin- 
ciples and processes of quantitative analysis. 
It was during these years of private 
study and practical work that young Mayer 
attracted the attention of a man whose 
personal influence was chiefly instrumental 
in determining the future direction of the 
student’s energies. Joseph Henry was at 
this time Secretary of the Smithsonian In- 
stitution, and for thirty years he had been 
identified with the advancement of pure 
science in America. Industrial science 
needs no advocates. Its importance is 
recognized by all. Its immediate connec- 
tion with material progress and its quick 
response to commercial demands are suffi- 
cient to bring within the ranks of its 
devotees the great majority of those who 
undertake laboratory work with a definite 
purpose. Henry had never underrated the 
value or the need of industrial science, but 
he had emphasized the importance of in- 
vestigation from the more unselfish stand- 
point of one who regarded intellectual 
acquisition as a priceless good in itself 
apart from all commercial recompense. He 
apprehended the brightness, the alertness, 
the originality of the Baltimore student, 
and accorded him that sympathetic recog- 
nition which constitutes the greatest stimu- 
lus that a young man can receive. The 
friendship of an acknowledged master 
makes a willing and easily directed pupil. 
Ideals of excellence are thus formed for 
life. Subsequent experience may some- 
times modify these, but they are rarely ever 
discarded. 
At the early age of twenty years Mayer 
was appointed to the chair of physics and 
chemistry in the University of Maryland. 
He had already during the previous year 
published his first contribution to science: 
the description of a ‘new apparatus for the 
determination of carbonic acid.’ This 
was soon republished in Germany. His 
SCIENCE. 
[N. 8. Vou. VI. No. 813. 
new duties absorbed now most of his time, 
but a second paper appeared in the Ameri- 
can Journal of Science, in 1857, on the esti- 
mation of the weights of very small por- 
tions of matter. In this he showed that 
by the deflection of a fine glass fibre it is 
possible to estimate a variation in weight 
so small as the thousandth part of a milli- 
gram. In 1859 he accepted a chair in 
Westminster College, Missouri, where two 
years were spent; but the equipment of 
this institution was insignificant and no 
original work was accomplished. The 
breaking out of the Civil War determined 
his return to Baltimore, and in 1863 he 
went to Paris, where two years were occu- 
pied in special study, chiefly under the 
direction of Regnault. The influence of 
the great French physicist, and the general 
atmosphere of the University of Paris, 
strengthened the bias in favor of pure 
science which had been received in youth 
from Henry. 
Soon after his return to America, in 1865, 
Professor Mayer was called to the chair of 
physics and chemistry at Pennsylvania 
College, in Gettysburg, which he gave up, in 
1867, to accept that of physics and astron- 
omy in Lehigh University. This in turn 
was renounced in 1871 for the purpose of 
joining in the upbuilding of the new Stey- 
ens Institute of Technology, at Hoboken, 
with which his connection continued up to 
the time of his death, July 18, 1897. It is 
with this institution, therefore, that his 
name will always be chiefly identified, 
though his researches were for the most 
part in channels somewhat removed from 
those that are usually characteristic of an 
engineering school. Its instrumental equip- 
ment was unusually good, and proximity 
to a great metropolis afforded the intellec- 
tual stimulus and the prompt recognition 
of merit which are wanting in isolated in- 
stitutions of learning. 
While connected with Lehigh University, 
