244 
NATLTORE 
[JuLy 13, 1899 
things are worshipped indiscriminately in each ; but Miss 
Kingsley has shown that in certain schools certain 
ideas are predominant, and her classification is based 
on a general survey which can afford to ignore minor 
inconsistencies. It is interesting to note that, according 
to Miss Kingsley’s observations, the African, to what- 
ever school of fetish he may belong, conceives of a great 
over-God, who has below him lesser spirits including 
man. But this fact does not necessarily support Mr. 
Andrew Lang’s recently promulgated theory as to the 
original purity and elevation of the religious beliefs of 
primitive races, though Miss Kingsley herself is inclined 
to identify her own conception of things with that she 
found current among the peoples she studied. We have 
merely touched on the principal sections of Miss 
Kingsley’s very interesting work, and have not space 
to do more than recommend its perusal to all those 
interested in the religions of the undeveloped races of 
mankind. The reader will find in it much material of 
the greatest scientific importance, while its anecdotes 
and lively style render it one of the most entertaining 
books of travel and observation that has appeared for 
many years. 
OUR BOOK SHELF. 
Catalogue of the Library of the Royal Botanic Gardens, 
Kew. (London, 1899.) 
THE issue of this catalogue fittingly commemorates the 
development, up to the last year of the nineteenth century, 
of an adjunct indispensable in the equipment of a centre 
of botanical research so deservedly famous as the Royal 
Botanic Gardens at Kew. The many botanists that have 
enjoyed the access to the library so freely allowed to 
workers in the Herbarium, and have learned to value the 
stores of information contained in it, will rejoice to have 
the catalogue as a guide to render the riches of the 
library still more accessible than in the past. But not to 
those alone that can visit Kew Herbarium is it likely to 
be welcome. Botanists living ata distance that precludes 
frequent visits to Kew Herbarium will find it most useful 
for reference as a guide to the literature of botany, and 
will value it accordingly. 
The size of the library may be judged from the fact 
that a rough calculation shows upwards of 15,000 separate 
entries of books or papers, besides numerous cross- 
references. Of course, all sides of botanical research are 
represented, from the more elementary to the most pro- 
found, from the most rigid study of botany as pure science 
to its practical applications to industries and arts, to 
folk-lore, and to its manifold links with other fields of 
study, scientific and literary. Occasionally one meets 
with a title that at the first glance seems to have little 
connection with botany, e.g. W. Ridgeway’s ‘‘ The Origin 
of Metallic Currency and Weight Standards,” yet these 
only serve to show the curious relations of botany to 
other studies. 
The entries are divided into four series, each arranged 
alphabetically :—(1) General, occupying 683 pages; (2) 
Travels, 43 pages ; (3) Periodicals and Serials, 47 pages ; 
(4) Manuscripts, 15 pages, large octavo. 
The catalogue has been prepared by Mr. B. Daydon 
Jackson, and is marked by the accuracy so characteristic 
of all his work in botanical bibliography. . Despite the 
peculiar risk of errors in transcribing and printing the 
titles and necessary details, many of which are in very 
unfamiliar languages, the freedom from errors is very 
noteworthy. 
An introduction to the volume from the pen of the 
Director of the Gardens gives a brief account of the 
NO. 1550, VOL. 60] 
leading facts in the formation of the library, which 
originated as a public library in 1852, when Miss 
Bromfield presented to the Gardens the botanical books 
that had belonged to her deceased brother, Dr. W. A. 
Bromfield. Sir William Hooker, on his appointment as 
Director in 1841, had offered to make his large private 
library and herbarium available for public use if they 
were suitably accommodated. This was done in a house 
provided for him as Director until 1852, when they were 
transferred to the present Herbarium, though still re- 
maining his private property. In 1854 the late George 
Bentham, F.R.S., very generously gave his large 
botanical library to the Herbarium, where in subsequent 
years he long continued those researches by which he so 
greatly advanced the science of botany. In 1867, after 
Sir William Hooker’s death, the Treasury sanctioned the 
purchase for the library of those botanical works that had 
belonged to him and that the library did not possess. 
Valuable legacies and gifts have also been received 
from other sources, and numerous serials are obtained in 
exchange; and purchases are made with occasional 
grants from the Bentham Trust. The sum expended 
from public funds in the formation of the library has 
been very small in comparison with its value, and has 
consisted of a small annual subsidy since 1849, supple- 
mented after some years by free binding by the Stationery 
Office. One important source of constant additions—the 
gifts of books and separate papers from the authors—is 
largely the result of the benefits experienced by the 
botanists that come from far and near to pursue re- 
searches at Kew. 
The catalogue would become still more valuable to 
botanists if there could be added a subject-division, even 
under large sections, of the multitude of titles that it 
contains. The difficulties of doing so are indeed con- 
siderable, but the aid to workers would be very great. 
The Larvae Collectors Guide and Calendar. By J. and 
W. Davis. Pp. 90. (Dartford: J. and W. Davis.) 
THE times of the appearances of the British macro- 
lepidoptera are given in this little book, together with 
notes on rearing lepidoptera from eggs, larve, and pupe. 
Young naturalists should find the volume useful in stock- 
ing their butterfly cages, and as a guide to the manage- 
ment of insects in the different stages of development. 
LETTERS TO THE EDITOR. 
(The Editor does not hold himself responsible for opinions ex- 
pressed by hts correspondents. Nether can he undertake 
to return, or to correspond with the writers of, rejected 
manuscrepts intended for this or any other part of NATURE. 
No notice ts taken of anonymous communications. ] 
A Lecture Experiment on the Relative Thermal 
Conductivities of Various Metals. 
Most lecture experiments on the conductivities of metals 
occupy too much time to be very effective, and in addition are 
often somewhat uncertain in their action. The following 
arrangement may be very quickly and simply put together, and 
by its aid the relative conductivities of a number of metals may 
be quantitatively determined in an interval of about a minute, 
the essential parts of the apparatus being capable of projection 
on a screen, 
A piece of brass tube, about 10 cm. in diameter and 20 cm. 
in length, is closed at one end by means of a brass disc. A 
number of holes are bored in this disc to receive the extremities 
of rods of copper, brass, iron, &c., each rod being 2°5 mm. in 
diameter and about 15 to 20 cm. in length. The rods are 
soldered in position perpendicular to the disc. : 
Each rod is provided with a small index, made from a piece 
of copper wire of about ‘8 mm. diameter, bent into the form 
shown in Fig. 1, a small arrow-head of blackened paper or mica 
being attached by shellac varnish. The rings forming part of 
each index are wound on a rod very slightly larger in diameter 
than the experimental rods. 
To start with, the brass vessel is inverted, an index is slipped 
