450 
just given birth to the art of photography, 
but the whole subject was up to this time 
empiric. By Bunsen and Roscoe it was 
placed on a scientific basis and the way 
blazed out for the many future investiga- 
tors in this field. 
One further study should be mentioned, 
that of Bunsen and Schischkoff on the 
theory of gunpowder. Gunpowder had 
been known for centuries; van Helmont 
had stated that its power was due to the 
production of gas, but beyond this little or 
nothing was known till these chemists took 
up the investigation of the gases formed 
and the powder residues, and formulated 
for the first time a theory of gunpowder. 
Here as in other cases the first incentive 
was given which resulted in the work of 
Karolyi and Abel and Nobel, and the many 
present-day workers in the field of explo- 
Sives. 
This résumé is but an outline of the more 
important work of this great chemist, dur- 
ing the first half century of his life. It was 
almost at the close of this half century that 
there was to come, as it were as a crown to 
his work, that great discovery with which 
the name of Bunsen will ever be most 
closely linked, spectrum analysis. For 
several years he had been interesting him- 
self much in blow pipe analysis, and it 
seems probable that the key to this dis- 
covery came, not as a result of long and 
patient search, but rather grew from his 
daily work of laboratory instruction. It 
was the discovery of the teacher rather 
than of the investigator. Associating with 
him his colleague, Kirchhoff, together they 
worked out the practical application of his 
discovery, and science stood armed with a 
new weapon, the spectroscope. Bunsen 
was the first to avail himself of the instru- 
ment and brought forth from the waters of 
Durkheim two new elements, rubidium and 
cesium. Later other new elements have 
followed, as indium discovered by Boisbau- 
SCIENCE. 
[N.S. Von. X. No. 248. 
dran and thallium by Crookes, and a host 
of ‘meta elements’ differentiated only by the 
spectroscope, the latest of them, victorium, 
needing not only this instrument but also 
the camera, to render its ‘lines’ apparent. 
But far more important than the mere dis- 
covery of new elements was the widening of 
man’s horizon in a new and unexpected 
way. Spectrum analysis was applicable 
not alone to those flames we could place 
before it within the confines of our labora- 
tories; the light of the sun and the stars 
could be studied equally well and a means 
was at hand for learning the chemistry of 
the heavenly bodies. Yet this was not all, 
for by the displacement of lines the motion 
of stars and other bodies in line of sight 
becomes known. Astro-physics is rendered 
possible by Bunsen’s work. 
The last of the great investigations of 
Bunsen were on calorimetry. The Bunsen 
ice calorimeter was described by him in 1870 
and rendered possible specific heat determi- 
nations, with quantities hitherto too small 
for investigation. While from this time 
his activity was much lessened, yet now 
and then papers continued to appear from 
his pen. The last few years of his life, 
however, were spent in the quiet retire- 
ment of the old university town which 
had so long been his home. As long as he 
was able he took great delight in showing 
visitors over his old laboratory, and the 
writer will long remember a pleasant hour 
spent with the old man in his laboratory 
some years ago, how he showed the rooms 
and places where this or that historic work 
was done, and what a delightfully genial 
man he was to a young stranger. 
As the old chemist’s sun was sinking to 
the west there came to Heidelberg, like a 
brilliant meteor, one whose fame far out- 
shone the older light. All things were 
changed, the old building passed, a new 
and magnificent laboratory took its place ; 
again students flocked to the Neckarthal 
