Marcu 31, 1923] 
NATURE 
437 

Obituary. 
| at Darmstadt on July 30, 1855; he studied pharmaco- 
Dr. J. G. LeatHem. 
a death of Dr. John Gaston Leathem on March 
19, at the age of nearly fifty-two years, removes 
a scholar who was prominent in the world of Cambridge 
mathematics. Coming from Queen’s College, Belfast, 
in 1891, he made his mark in the triposes of 1894 
and 1895. He held the Isaac Newton studentship for 
astronomy and physical optics during the period 
1896-99, soon gaining also a fellowship at St. John’s 
College. His interests were then mainly in electro- 
dynamic theory; and the work of his studentship 
produced a memoir (Phil. Trans., 1897, pp. 89-127). 
which ought to be classical, in which the theory of the 
Magneto-optic rotation of light and the cognate 
reflection effect were finally systematised and co- 
ordinated, under the test of laborious comparisons 
with the numerical experimental data. 
In due course Dr. Leathem became mathematical 
lecturer at St. John’s College, and afterwards univer- 
sity lecturer: and for a series of years he exerted a 
wide influence on the teaching. For the mathematical 
tripos he was an examiner on as many as six occasions, 
two of them (1912, 1913) after he had been withdrawn 
from all teaching except an annual advanced course 
on electrodynamics. For he had become senior 
bursar of his college in 1908, and henceforth he threw 
himself into its external affairs and general adminis- 
tration with assiduity and practical success. 
In 1905 Dr. Leathem took up the editorship, in 
conjunction with Prof. E. T. Whittaker, of a series 
of Mathematical Tracts projected by a Cambridge 
group of lecturers, which, in numerous volumes, has 
become under their care an important survey, almost 
an encyclopedia, of domains of recent higher mathe- 
matics. To this undertaking he contributed the earliest 
volume of the series, and one on optical systems. 
His own later special investigations, exhibiting the 
geometrical trend that is associated with the Irish 
school, thus including applications of conformal trans- 
formations to physical problems, were published mainly 
by the London Mathematical Society and the Royal 
Irish Academy. A note in Roy. Soc. Proc. established 
an unexpected mode of interaction between a magnet, 
supposed to consist of revolving electron-systems, and 
a varying electric field, too small, however, to permit 
of experimental scrutiny. 
_ During the War Dr. Leathem felt bound to volunteer 
for work in the Research Department at Woolwich 
Arsenal, then in need of mathematical help, handing 
over as much of his bursarial work as was possible 
to senior colleagues. About two years ago he had 
to submit to a sudden and very drastic surgical opera- 
tion: in time he recovered, and though never strong 
again, he resumed his activities with all the previous 
zeal and judgment. But the mischief could only be 
delayed, not removed : and his loss will now be deeply 
felt not only in his own college but also throughout 
the university. J: L. 












Dr. E. A. MERCK. 
Tue death took place at Darmstadt on February 25 
of Privy Councillor Dr. E. A. Merck, senior partner of 
the chemical works of E. Merck. Dr. Merck was born 
NO. 2787, VOL. 111] 
logy and chemistry, and took his degree in Freiburg 
i, B. under Ad. Claus. He then took over the Engel- 
apotheke, which had been in the possession of the family 
of Merck since 1668, and became one of the managers 
of the chemical works of E. Merck. 
The works, which were then on only a modest scale, 
were greatly enlarged through the energy and initiative 
of Dr. Merck and his cousin, Louis Merck, who was his 
partner, and developed into one of the greatest manu- 
factories of preparations for medical purposes. To the 
production of drugs was added that of alkaloids, 
the preparation of synthetic remedies (for example, 
“veronal”’), and various sera. In response to the 
demand of chemists for pure reagents, the production 
of chemically pure preparations and solutions for volu- 
metric analysis was taken in hand, and the firm’s 
products became famous throughout the world. The 
connexion between the industry of chemical prepara- 
tions on one hand and the pharmaceutical chemists 
and physicians on the other was steadily maintained 
by the literary publications: ‘‘ Mercks Jabresbericht,” 
“ Mercks Index,” and ‘“‘ Mercks Reagenzienverzeichnis.”’ 
Dr. Merck took an important part in all these de- 
velopments. At the same time he worked continually 
for the improvement of the training of pharmaceutical 
chemists and the social position of the whole chemical 
profession. For six successive years he was president 
of the Verein Deutscher Chemiker, and he represented 
German chemistry at many international gatherings. 
His strong historical interest led him to give particular 
attention to the work of Liebig, and he was one of the 
founders of the Liebig Museum at Giessen. 

WE regret to announce the following deaths : 
Prof. A. S. Dogiel, professor of histology in the 
University of Petrograd, whose investigations on 
the histology of the peripheral nervous system are 
well known. 
Prof. A. S. Flint, emeritus astronomer of the 
Washburn Observatory, University of Wisconsin, on 
February 22, aged sixty-nine. 
Prof. W. S. Haines, professor of chemistry, materia 
medica, and toxicology at Rush Medical College, 
and professor of toxicology in the University of 
Chicago, on January 27, aged seventy-two. 
Sir Joseph M‘Grath, a vice-president of the Royal 
Dublin Society, and registrar of the National Uni- 
versity of Ireland since 1908, on March 15, aged 
sixty-four. 
Mr. W. Pearson, for nearly fifty-eight years pro- 
sector to the Museum of the Royal College of Surgeons 
of England, on March 15, aged eighty-two. 
Sir Thomas Roddick, formerly professor of surgery, 
McGill University, and the first Colonial president 
of the British Medical Association, at its Montreal 
meeting in 1897, on February 20, aged seventy-six. 
Sir William Thorburn, emeritus professor of 
clinical surgery in the University of Manchester, on 
March 18, aged sixty-one. ; 
Prof. J. Trowbridge, emeritus professor of physics 
at Harvard University, on February 18, aged seventy- 
nine. 
Mr. E. W. Vredenburg, of the Geological Survey of 
India, on March 12. : 
Prof. N. E. Wedensky, professor of physiology in 
the University of Petrograd. 
