LO2 
NATURE 
[SEPTEMBER 25, 1913 
the production of new forms by either physio- 
logical or morphological variation becomes still 
more considerable. 
Dr. Perkins, and apparently all the contributors 
to the “Fauna” agree that Hawaiia is oceanic. 
Dr. Perkins summarises the evidence in his 
“Review of the Land-Fauna,” the last published 
part. He further points out that nineteen- 
twentieths of the endemic species are found in the 
forest belt. This is in accordance with theory, 
for the isolation as varieties leave the coast land 
is to be expected to be helpful to species forma- 
tion, though the largeness of the proportion is 
doubtless helped by the destruction of the low- 
land vegetation. The inconspicuousness of the 
fauna and flowers is noted, but the paucity of 
individuals—some parts are barren to the collector 
owing to the devastation of carnivorous ants— 
is doubted, as is interbreeding as producing 
diminished fertility. 3325 species of insects are 
known, and practically all the endemic species 
are of small size and special habits; many are 
flightless. Their large amount of variability is 
interesting as well as a distinct tendency to 
specialisation in variation in different localities. 
Dr. Perkins clearly considers that the fauna 
arose from a very few immigrants, which have 
varied to form the present large genera and groups 
of allied genera. Some genera are confined to one 
of the six forest-clad islands, and in large genera 
few species from different islands are identical. 
Isolation even without selection is supposed to 
have brought about change, and the extreme 
difficulty that the systematist has in limiting his 
species is ascribed to the absence of agencies 
by which natural selection works. On every 
theoretical point Dr. Perkins has some fertile 
suggestion, but the writer hesitates to quote more 
because such might be misconceived by the reader, 
who had not the altogether unique facts before 
him. J. StanLey GARDINER. 
SIR W. IN; HARTLEY, FR:S. 
Ee the death of Sir Walter Noel Hartley, the 
scientific world has lost a man who un- 
doubtedly has enriched it in very many ways. 
Although perhaps his name is more intimately 
connected with work upon absorption spectra and 
their relation to the constitution of organic com- 
pounds, yet Hartley also carried out most impor- 
tant investigations in many other branches of 
spectroscopy. 
Sir Walter Hartley was born on February 2, 
1846, and was appointed professor of chemistry 
in the Royal College of Science, Dublin, in 1879, 
a position he held until his retirement under Civil 
Service regulations in 1911. One of the founders 
of the Institute of Chemistry, he was a vice- 
president from 1900 to 1903. He was elected a 
Fellow of the Royal Society in 1884, and was 
awarded -the Longstaff medal by the Chemical 
Society in 1906. He received his knighthood on 
the occasion of the opening of the new buildings 
of the Royal College of Science, Dublin, by the 
NO. 2291, VOL. 92] 
King and Queen in rg1r. His death, which 
occurred on September 11, at Braemar, was due 
to heart failure following on bronchitis. 
Hartley’s investigations were almost entirely 
connected with spectroscopy, and his published 
papers deal with three of its principal branches, 
namely, flame spectra, spark spectra, and absorp- 
tion spectra. Perhaps the most striking thing in 
connection with all his work is the, singular 
interest which he instilled into it. To many, 
spectroscopy may appear as a somewhat dry 
statistical study of the wave-lengths of emission 
lines and absorption bands, but no one on reading 
Hartley’s numerous and varied contributions to 
the literature of the subject could lay such an 
accusation against his work. There is to be found 
there no mere dull compilation of accurate 
measurements, but copious evidence of wonderful 
insight and keenness. In all his work, Hartley 
showed himself a pioneer in the application of 
spectroscopic methods to the study of the nature 
and properties of the chemical atom and molecule, 
and it is from this that the great interest of his 
work arises. 
In 1872 Hartley became the possessor of Dr. 
W. A. Miller’s spectroscope, and he not only 
showed that it was possible to obtain the whole 
spectrum in focus upon a flat plate with the use 
of quartz prisms and unachromatised quartz 
lenses, but he was the first to use dry plates in 
the photography of spectra. The original 
apparatus was modified considerably, and amongst 
other improvements it was so devised that a 
number of photographs could be taken on the 
same plate. This in itself marked a great advance 
in technique. Hartley in the early days almost 
entirely restricted himself to the use and study 
of spark spectra. In 1883 he published a series 
of photographs of spark spectra, and in 1884 he 
put forward, in conjunction with Dr. W. E. 
Adeney the wave-lengths of the lines in these 
spectra. This later paper also contained the wave- 
lengths of the lines due to air which are of such 
importance in all spark spectra observations. 
The publication of these wave-lengths marked a 
very important advance in spectroscopy. - 
Later, Hartley turned his attention to the spark 
spectra of solutions of metallic salts, and it is 
to him that we owe almost the whole of our 
knowledge of the nature and character of the 
lines in these spectra. From a study of the effect — 
of concentration it was soon noted that all the 
lines do not disappear at the same dilution. 
Hartley found that there exists a constant relation 
between the dilution and the appearance or dis- 
appearance of certain lines of each metal, and 
based on this he was able to found a system of 
quantitative analysis. The value of this method 
he proved by applying it with perfect success to 
the analysis of an Egyptian coin. Similarly, from 
his knowledge of the relative persistence of 
spectrum lines, he was the first to prove the 
presence of gallium in the sun and many of the 
stars. In the same way he showed the remarkably 
extensive distritution of the rare earth metals, 
