782 
NATURE 
[JUNE 9, 1923 

Girls’ Radio Clubs of the States Relations Service, 
Department of Agriculture. In Circular No. 120 it 
was shown how a single circuit and in Circular No. 121 
how a double circuit crystal-detector set could be 
made out of ordinary domestic materials. It is now 
shown how the operation of either set can be im- 
proved by the use of a very simple and cheap con- | 
denser connected across the telephone receivers and | 
a similar one connected in series with the antenna. 
Clear instructions are also given for constructing a 
simple loading coil so that longer waves can be 
received. The condenser in series with the antenna 
makes it easy to tune to wave lengths of less than 
300 metres, whilst the condenser across the telephone | 
receivers increases the intensity of the signals. The 
loading coil enables time signals, etc., to be received 
from high power stations. The parts for the aux- 
iliary condensers cost about 80 cents, and the parts 
for the loading coli about 3 dollars. 
Messrs. W. HEFFER AND Sons, Ltd., Cambridge, 
have just circulated a very full and useful catalogue 
(No. 224) of scientific books and serials numbering 
upwards of 2000 titles and classified under the 
headings of agriculture, husbandry, and farriery ; 
anthropology and ethnology; botany; chemistry, 
chemical technology, and metallurgy; geology, 
mineralogy, and paleontology ; zoology and biology ; 
physiology, anatomy, and medicine; psychology and 
psycho-analysis portraits of men of science; and 
mathematics, physics, and engineering. The list is 
especially interesting from the fact that many of the 
works are from the library of the Jate Sir William 
Ramsay. We note that Messrs. Heffer are offering 
for sale in one lot a large collection of books, pamphlets, 
and serials dealing with aeronautics. 
THE cinematographic film, entitled ‘‘ The Wonder- 
land of Big Game,” which Major A. R. Dugmore is 
showing at the Polytechnic Hall, Regent Street, 
London, is certainly one of the finest of its kind and 
deserves the attention of all interested in natural 
history. It is the result of a special expedition to 
East Africa made by Major Dugmore in 1922, and it 
is shown in connexion with a most charming and 
lucid explanatory lecture delivered by Major Dugmore 
himself. The outstanding merit of this film is its 
entire truthfulness and freedom from fake. It shows 
about thirty species, not only in their natural sur- 
roundings, but also under perfectly natural conditions, 
unharried by the big game hunter and usually un- 
conscious of the presence of the harmless photo- 
grapher. Save for occasional shots at lions, only one 
shot was fired at an animal during the expedition, | 
and that was one intended merely to turn a rhinoceros | 
from a headlong charge upon the camera. The 
animals are shown grazing at their ease upon the 
veldt, moving through the forest glades, or coming | Board 
down to the water-holes to drink. The pictures of | 
the common and Grevy’s zebras, rhinoceros, elephant, | 
buffalo, oryx and other antelopes, and, above all, of | 
the reticulated giraffe are of very great interest ; no 

one, with an experience wholly derived from Regent’s | 
Park, can imagine the grace of giraffes in free motion. 
NO. 2797, VOL. IIT] 
The flashlight portraits of a lion and his mate also 
deserve special notice. Though perhaps less thrilling 
than some of the photographs of lions exhibited at 
other places recently, they are true to life, showing 
the animals as they normally behave, and not as 
they are when, infuriated by pain, they are held in 
a powerful trap, concealed by some convenient bush 
from the lens of the camera. Portions of the film 
will appeal also to those who areinterested in anthropo- 
logy, physical geography, and geology. Major Dug- 
more deserves success; and we hope that his lecture 
will draw large audiences for a long time to come. 
Tue work that has been carried on by the British 
Science Guild since 1905, with the object of bringing 
about a better public appreciation of the value of 
science, isin many respects unique. There is no body 
that has done more to bridge the gap between the 
public and the man of science. Among various 
matters of general interest that are now engaging 
the attention of its various committees may be 
mentioned the adequate representation of science at 
the British Empire Exhibition and the question of a 
British Empire patent. The Catalogue of British 
Scientific and Technical Books has proved a valuable 
piece of work, and it is satisfactory to note that sales 
and contributions have brought in a sum which 
almost equals the cost of production. The publica- 
tion of a new edition is now being taken in hand. 
An interesting step has been the issue of publicity 
leaflets summarising recent scientific developments 
in popular form. The first of the series, by Prof. 
J. C. McLennan, deals with ‘‘ Helium and its Uses.” 
The production in mass of this non-inflammable gas 
for use in airships is a fascinating story, and there is 
no more striking example of scientific achievement 
during the War. The second leaflet, by Prof. J. A. 
Fleming, on “The Thermionic Valve” is now in 
preparation. There is no doubt that this new 
departure will be of service in promoting the objects 
of the Guild. Naturally, however, such propaganda 
work cannot be conducted without the “ sinews of 
war.”’ At the special meeting at the Mansion House 
on February 27, and again at the annual dinner on 
May 30, reference was made to the appeal now being 
issued by the Guild for contributions to form a fund 
of 50,0001. to enable its programme to be energetic- 
ally developed. It is to be hoped that this appeal, 
which has received most influential support, will 
meet with a generous response. 
THE second, or ladies’, conversazione of the Royal 
Society this year will be held at Burlington House 
on Wednesday, June 20. 
Dr. A. BowMan, senior naturalist on the staff of 
the Fishery Board for Scotland, has been appointed 
superintendent of scientific investigations under the 
Pror. C. MoureEu, president of the Société Chimique — 
de France, will deliver a lecture on “‘ Les gaz rares 
des sources thermales, des grisous et autres gaz 
naturels ’’ at the rooms of the Chemical Society, — 
Burlington House, on Thursday, June 14, at 8.30 P.M. — 

