138 
the native English trees, and also a large number 
of foreign species, finding the conditions suitable 
for their growth. How long these conditions will 
remain favourable is problematical, a remark which 
applies also to Mr. Whitton’s goodly list of some 
300 species of flowering plants given in chapter vi. 
The geology of the district is necessarily 
“tame,” but since Mr. F. W. Rudler is responsible 
for that chapter (chap. ii.), it is perhaps scarcely 
necessary to say that it will be found both interest- 
ing and instructive. The only regret is that the 
author did not “let himself go” more freely in 
discussing some of the generalisations which have 
of late years been based upon the detailed study 
of gravels and superficial deposits generally. In 
connection with the climate of Hampstead (chap. 
iii,, by Mr. E. L. Hawke), it is of interest to 
note that the sunshine record, as compared with 
that of the city, more nearly approaches that of 
Berkhamstead, which is tolerably clear of London 
influence. Thus the total number of hours of 
bright sunshine during 1910 was 1372, as com- 
pared with 1348 at the Hertfordshire station, 
1183 at Camden Square, and 993 at Bunhill Row. 
So much for the effects of atmospheric pollution in 
the City of London! Bird-life (chap. vii.) is dealt 
with by Mr. Herbert Goodchild, who gives a very 
clear account of the particular conditions favour- 
able and unfavourable to an avifauna. One of his 
observations is very significant: ‘Adjoining the 
heath are several private woods, a form of owner- 
ship which tends to the preservation of species 
that might otherwise be lost to the district, since 
in such woods and coppices the birds are safer 
from molestation. As some of these woods adjoin 
the public domain, an observer may see on the 
latter many species of birds that might be driven 
away if all the woods were public.” The writer 
of this notice has long ago come to the conclusion 
that the preservation of open spaces solely from 
the point of view of the “recreation and enjoy- 
ment of the public” is in many cases quite the 
reverse of a boon from the point of view of the 
naturalist. Mr. Goodchild is, of course, an advo- 
cate of the study of bird-life by the modern method 
—i.e. the field-glass and camera, and not by the 
gun. It is fortunate for the district, also, that 
it comprises the Brent reservoir, and that that 
well-known observer Mr. J. E. Harting was a 
former resident, and kept observations of the birds 
for many years. 
The chapter on mammals, fishes, and reptiles, 
by Mr. Hugh Findon, will also surprise many 
readers who are unprepared for the survival of 
such a number of species within sight of the 
metropolis. The existence of badger-earths, still 
apparently tenanted, is certainly remarkable, but 
here, again, the preservation of this notoriously 
shy animal is due to the inclusion of the earths 
(a figure of which we reproduce) in the private 
grounds of Ken Wood, the owner of which estate 
has always been a sympathetic conservator of 
this interesting denizen. Dr. O’Brien Ellison’s 
chapter on insect-life serves to emphasise the com- 
plaint so frequently made by entomologists in this 
NO. 2292, VOL. 92] 
NATURE 
[OcToBER 2, 1913 
country that local collectors so generally concen- 
trate their attentions upon the Lepidoptera to 
the neglect of other orders. There are surely more 
than twenty-seven species of Coleoptera in the 
district, to say nothing of Hymenoptera, Diptera, 
and Microlepidoptera. The list of Lepidoptera, by 
the way, is marred by a number of misprints, It 
only remains to add that there are chapters on 
| molluscs and on pond-life by Mr. Hugh Findon 
and Mr. James Burton respectively. 
The Hampstead Scientific Society has certainly 
done good service in publishing this volume, which 
is a typical specimen of the kind of work which 
local societies should undertake. For a district 
such as that dealt with—viz. within the three- 
mile radius from the flagstaff on the summit of 
the heath—a book like that before us is not only 
of immediate utility, but is certain to acquire in- 
creased value as time moves on and the influence 
of urbanisation becomes more and more pro- 
nounced. Already many of the species recorded 
are taken from old publications, and are now 
extinct. The general impression produced by the 
perusal of the volume is one of marvel at the 
persistence of so much that is “natural” in the 
area described. R. M. 
PROF. HUGH MARSHALL, F.R.S. 
4g the untimely death of Prof. Hugh Marshall, 
which took place in London on September 5, 
chemistry has lost, at the early age ot forty-five, 
one of the nowadays comparatively few prominent 
men who devoted their energies to the investigation 
of subjects connected with the inorganic and 
mineralogical branches of the science, and the 
University of St. Andrews an active and useful 
member of the professorial staff of Dundee 
University College. 
It is not a disparagement to say that Dr. 
Marshall’s most brilliant discovery—that of the 
persulphates, in 1891—was due to one of those 
fortunate chances, not infrequent in science, where 
experiments designed to elucidate a certain defi- 
nite question lead to some new discovery of a 
wholly different description and often of much 
greater consequence; for, no sooner was the 
discovery made than its author was quick to 
discern that substances of far-reaching importance 
had fortuitously presented themselves to him and 
to prosecute their examination with exceptional 
vigour and success. The subject under immedi- 
ate investigation was the oxidation of cobalt salts 
by electrolysis in the then comparatively little 
employed “divided ”’ electrolytic cell, and on pass- 
ing a current of electricity through ‘“‘a fairly acid 
solution of cobalt and potassium sulphates,” with 
a view to prepare potassium cobalt alum, small 
crystals slowly separated, which proved on 
analysis to consist of potassium persulphate. The 
discovery of the persulphates at once brought Dr. 
Marshall’s name into prominence, while the 
assiduity and skill with which he continued his 
examination of them speedily marked him as a 
rising inorganic chemist. 
