212 

ished, while that of soft steel or soft iron was 
increased; and in both cases the effect was ap- 
proximately proportional to the square of the 
magnetising force. When the magnetisation was 
transverse a similar effect was observed. 
The next subject investigated by Adams was 
the phenomenon of the effect of light in reducing 
the resistance of selenium, which had _ recently 
been discovered by Mayhew. With great patience 
and experimental skill he showed that the effect 
was not due, as had been supposed, to any heat- 
ing of the selenium, but was a genuine result of 
illumination; and he proved that the change of 
resistance was greater for yellow-green rays than 
for any other part of the spectrum. 
Adams was one of the founders of the Physical 
Society, in 1875; and to its first volume of Pro- 
ceedings he contributed a description of a new 
form of polariscope for determining the angle 
between the optic axes of biaxial crystals. The 
crystal slice to be examined was placed between 
two pieces of glass, one being a hemisphere and 
the other a shallower section than a hemisphere, 
the convex surfaces having a common centre in 
the crystal slice. The combination was placed in 
oil between the usual crossed Nicol prisms, and 
could be tilted through any desired angles so as 
to bring first one and then the other of the optical 
axes of the crystal into alignment with the axis 
of the instrument, thus enabling the angle be- 
tween the axes to be accurately measured without 
corrections for the refractive index. 
In 1880 Adams was chosen president of section 
A of the British Association, and delivered an 
address dealing generally with recent progress in 
physics. He also presented a report of a com- 
parison between the magnetograph curves from 
the magnetic observatories of Kew, Stonyhurst, 
Lisbon, Coimbra, Vienna, and Petrograd. In the 
following year he continued his magnetic investi- 
gations with a paper on the connection between 
magnetic disturbances and earth-currents. He 
wrote also on the development of lighthouse illu- 
mination, and with Dr. Hopkinson examined the 
performance of the De Meritens dynamos at the 
North Foreland lighthouse. As president, in 
1884, of the Institution of Electrical Engineers, 
he took for the subject of his inaugural address 
the topics of the growth of electrical science and 
the testing of dynamo machines and incandescent 
lamps. He wrote a series of articles on electric 
light and atmospheric.absorption, and another on 
lighthouse illuminants and apparatus, for publica- 
tion in the Electrician in the years 1885 and 1886. 
After some years he returned to the subject of 
magnetic disturbances as recorded simultaneously 
on the magnetographs at several observatories, in 
a paper which was published in the Philosophical 
Transactions (vol. cviii.) in 1893. To the British 
Association report of 1898 he contributed an 
account of the determination of the Gaussian mag- 
netic constants made many years previously by 
his elder brother, the astronomer, John Couch 
Adams. : 
Grylls Adams served on the council of the Royal 
Society from 1882’ to 1884, and again from 1896 
NO. 2373, VOL. 95] 
NATURE 

[APRIL 22, 1915 
to 1898. He was president of the Physical 
Society in 1879. In 1883 he delivered a series of 
Cantor lectures on the subject of electric light- 
ing. He retired from the professorship at King’s 
College in 1906. He has left a widow, three sons, 
and one daughter. 

NOTES. 
WE record with much regret the death on April 16, 
at sixty-five years of age, of Mr. Richard Lydekker, 
F.R.S., distinguished by his original work and 
numerous writings on all aspects of natural science, 
and a constant contributor to NaTurE for many years 
to within a few days of his death. 
Tue Paris Geographical Society has just made a 
special award of a gold medal to Dr. J. Scott Keltie, 
for his long and distinguished services to geographical 
science. 
CotoneL G. W. GOETHALS, engineer of the Panama 
Canal, and Sir Thomas Shaughnessy, president of the 
Canadian Pacific Railway Company, have been elected 
honorary members of the Institution of Civil 
Engineers. 
Tue British Medical Journal announces that the 
Louis Livingston Seaman medal for progress and 
achievement in the promotion of hygiene and the 
mitigation of occupational diseases has been awarded 
to Major-General W C. Gorgas. 
Tue Warren prize of the Massachusetts General 
Hospital, of the value of 1ool., and awarded triennially, 
is offered for the year 1916 for the best essay on some 
special subject in physiology, surgery, or pathology. 
Further particulars are obtainable from Dr. F. A. 
Washburn, at the hospital named. 
We learn from the Lancet that the Hutchinson 
Museum has been acquired by the Medical School of 
Johns Hopkins University. The collection comprises 
original coloured drawings; coloured plates taken 
from atlases, books, and memoirs; engravings, wood- 
cuts, photographs, and pencil sketches, in some cases 
with the letterpress or manuscript notes attached. 
The collection illustrates the whole range of medicine 
and surgery, but particularly syphilis and skin 
diseases. 
Sir Tuomas Ciouston, a leading authority upon 
the subject of mental diseases, died in Edinburgh on 
April 19, at nearly seventy-five years of age. He was 
lecturer on mental diseases at Edinburgh University, 
and was the author of a number of important works 
on disorders of the mind. He was president of the 
Royal College of Physicians, Edinburgh, in 1902-3, 
and was for some time editor of the Journal of Mental 
Science. 
Tue death is announced of Mr. J. B. A. Légé, who 
made the first tide-predicting machine for the late 
Lord Kelvin. He was the constructor of signalling 
lamps and other apparatus invented by Admiral Sir 
Percy Scott and used in the Navy. Among Mr. 
Légé’s inventions: may be mentioned horological 
mechanisms,. torpedoes, .and~ direct-acting petrol 
engines: , 

