JUNE 5, 1902] 
NATURE 135 
to send to the Board without delay for identification specimens 
of any insects suspected to be the Colorado beetle. The Board 
will be pleased to supply copies of a leaflet, with a coloured 
illustration of the beetle, post free and free of charge upon 
application. Letters or packets containing specimens, and 
applications for leaflets, should be addressed to the Secretary, 
Board of Agriculture, 4 Whitehall Place, London, S.W., and 
need not be stamped. 
AN interesting ceremony was performed at Chamounix on 
May 19, M. Joseph Valat, the founder of the Roches-Rouges 
Observatory, being in the chair. The bust of Charles Durier, 
a former president of the French Alpine Club, was presented to 
M. Simon, the manager, by M. Schrader, the president of the 
society. A letter was read from M. Janssen, who was prevented 
by reasons of health from being present. M. Simon was sur- 
rounded by a group formed by the Mont Blanc guides, who 
ascend Mont Blanc every week in order to bring back to 
Chamounix the automatic readings registered at the Janssen 
Observatory. Speeches were delivered by MM. Chautemps, the 
member for Chamounix to the Chambre des Députés, Morel, 
Fredel, president of the Mont Blanc section of the Alpine Club, 
Paul Joanne, an intimate friend of Charles Durier, Prideux of 
the Academy of Sciences, and other influential members of the 
Alpine Club. 
AT the recent general meeting of the Paris Geographical 
Society, the following prizes awarded for this year were 
announced :—The chief gold medal of the Society to Captain 
Joalland, for the Joalland-Meynier expedition to Central Africa, 
with a silver-gilt reproduction of the medal to Captain Meynier. 
The Herbet-Fournet prize, a gold medal and 6000 francs, to 
Governor Emile Gentil, for work on the Tchad (1895-1901). 
Silver medals are awarded to the principal officers of M. Gentil’s 
expedition. The Ducros-Aubert prize, three gold medals, to 
M. V. A. Bernard and Dr. Huot, for the Chari-Sangha 
exploration, and to M. Ch. Perdrizet, for his work in West 
Africa. The Conrad Malte-Brun prize, gold medal, to Captain 
Ch.-Lemaire, for the scientific exploration of Katanga. The 
Henri Duveyrier prize, gold medal, to Captain E. A. Lenfant, 
for scientific explorations on the Senegal and Niger. The Louis 
Bourbonnaud prize, gold medal, to M. P. Bons d’Anty, for 
explorations in South China. The Jean-Baptiste Morot prize, 
gold medal, to Captain E. Julien, for explorations in the basin 
of the Oubanghi. The Léon Dewez prize, gold medal, to 
M. Hugues Krafft, for his journey into Russian Turkestan. The 
Pierre-Félix Fournier prize, special medal and 1300 francs, to 
M. H. Réraldi, for his book ‘* Cent Ans aux Pyrénées.” Silver 
gilt medal of the Society to MM. Marcel Dubois and Auguste 
Terrier, for their book ‘‘ Un Siécle d’expansion coloniale.” 
The Alphonse de Montherot prize, silver medal, to M. Georges 
Brousseau, for his explorations on the Congo. The Charles 
Grad prize, two silver medals, to) M. Maurice Superville and 
Lieut. Bos, for their exploration of the Kotto. The Alexandre 
Boutroux prize, silver medal, to M. Albert Lesieur, for his 
explorations on the French Congo, The J. C. Janssen prize, 
silver medal, to M. Emile Belloc, for his study of the physical 
geography of the Pyrenees. The William Huber prize, silver 
medal, to M. de Martonne, for his geographical studies. The 
Jomard prize to M. Cl. Madrolle, for his book ‘‘ Histoire de 
la Compagnie des Indes en Chine.” Competitive prizes of the 
Society, two silver medals, each accompanied with 400 francs, to 
MM. P. Pasquier and M. A. Breschin. 
Own Thursday evening last the members of the Camera Club 
and their guests were assembled to listen to a discourse by Dr. 
E. F. Griin on the new fluid lens with which he has recently 
been obtaining some very excellent photographs of theatrical 
NO. I701, VOL. 66] 
and other night scenes. The use of a fluid lens is a very old 
idea, but it soon fell out of use when homogeneous glass could 
be made properly and the combination of flint and crown 
successfully mated. The object of using fluid in lenses at this 
early time was simply to overcome certain optical deficiencies of 
the single glass lens. Dr. Griin’s idea in adopting this form of 
lens is to increase very considerably the rapidity of its action, and 
so successful has he been that he can produce very excellent 
photographs with short exposures with ordinary night illumina- 
tion, his lenses working at # 1°4 and even f.0°5. The slides 
made from the photographs he has taken showed several snap- 
shots taken at different theatres without any previous prepara- 
tion either as regards the actors and actresses, or the stage 
illumination, and these were quite sufficient to give one an idea 
of the important future for such a lens. One of the chief points 
in the lens is the great depth of focus which is shown in the 
individual pictures, for not only are the performers in front of 
the stage in focus, but the scenery at the back is quite sharp as 
well. The very great rapidity of the lens led Dr. Griin to 
attempt to take kinematograph pictures of stage performances. 
The results, although not of a very high order, showed, however, 
that with alittle more experiment just as good pictures of night 
scenes can be secured as are displayed to-day in kinematograph 
pictures taken in daylight. There is little doubt that Dr. Griin 
has indicated the great possibilities of his new lens, and many 
scenes which could not be depicted on account of their apparent 
lack of sufficiently brilliant illumination may now be caught in 
the meshes of this photographic net. 
WITH reference to the correspondence which has recently 
been appearing in these columns on the misuse of coal, we see 
from last week’s Z/ectrical Review that a company has just been 
incorporated in America for the commercial fixation of nitrogen. 
The company is to erect a factory at Niagara, where it already 
has one commercial unit in operation. This consists of a 
chamber about 10 feet high, through which cool dry air is 
passed. The air is subjected to the influence of electric dis- 
charge in the form of small-current high tension arcs, whereby 
oxides of nitrogen are formed. These oxides are led to an 
absorption tower, where they are brought into contact with a 
suitable compound of a substance of which the nitrate is desired ; 
caustic soda or potash, for example, are used for the preparation 
of sodium and potassium nitrate respectively. If led into water, 
nitric acid can be obtained. It is said that part of the object of 
Lord Kelvin’s recent visit to the States was to see the working 
of the process, and that he was greatly interested and much 
impressed by its success. 
IN a short note contributed to the Adté dec Lincez, xi. 9, 
Signor G. Celoria urges the desirability of including the teaching 
of astronomy in the curriculum of every Italian university and of 
making the subject a compulsory part of the science courses. 
At present the regulations require astronomical classes to be 
held at all universities which possess an observatory, but 
Signor Celoria considers that much useful teaching may be given 
without the help of instruments, and further, that the present 
limitation tends to confine the study of astronomy to its purely 
practical aspect. 
In the University of Colorado Studies, Messrs. William 
Duane and Charles A. Lory describe a simple electric thermostat 
for keeping the temperature of a bath constant to within a 
thousandth of a degree Centigrade for a considerable time. 
The heat is supplied by an electric current, which in the case of 
a conducting liquid flows through the liquid itself, and in the 
case of a non-conducting fluid flows through wires suspended in 
the bath. A system of tubes containing a liquid with a large 
temperature coefficient of expansion is placed in the bath, and 
by means of a suitable mechanism the expansion of this liquid 
