Sept. 26, 1872J 



NATURE 



-145 



Combes, M. d'Eichfal came to the assistance cf the embryo as- 

 scciatinn, and oil January 17 of th's year a provisional council 

 was appointed, with M. C. liernard as president, and on April 

 22 the French Association was constituted, and already numbers 

 upwards of 700 nicmbers. The Biitish Associat'oa when it 

 started in 1831 had only 370 members, whereas now it numbers 

 many thousands, and can spend 2,000/. yearly for the progress of 

 science. M. Cornu hopes that the French Association may be- 

 come similarly pro-perous, as indeed it seems to bid fair to do, 

 fur already, as M. Georges Massen, the treasurer, intimated, it 

 has a capital of 140,000 francs, and can dispose of an annual 

 revenue of 16,000 francs. 



M. Laussedat gave an interesting lecture on "The Ser- 

 vices which Modern Science can render to the Ait of War," in 

 which the starting sentenc; is that "Germany triumphed over 

 France by numbers, discipline, and science." This was followed 

 by a paper from M. Le Fort, on the Reform of Military 

 Surgery. In the meetings of sections which followed, medical 

 subjects received permanent attention, and called forth many 

 pape:s of great value. 



In the Anthropological Section, M. Lagneau read a careful 

 paper on "The Ethnology of the Popu'ations of the south-west 

 of France, particularly of the basin of the Garonne and its 

 aflluenL"!," M. Paul Lopenardone on 'Prognathism," in which 

 he give some new measurements, and described a new method 

 of measuring skulls ; M. Parrot gave some details of the Cave 

 of Ixcideuii (Dordogne), the variety of bones and other remains 

 in which are of the greatest interest to anthropologists. Most of 

 the other papers in this section were on subjects similar to the 

 last, the prehistoric remains of various kinds found in caves, dol- 

 mens, etc., a department of Archaioloc;)' 10 which much more 

 has been done in France than in this country. M. Cartailhac 

 went the length of saying tliat two populations belonging to pre- 

 historic times could be distinguisiied as inhabiting the south of 

 France ; one warlike ai d givt-n to the chase, who knew the beds 

 of flint, and could cut it to perfection, and which was armed 

 with the Low ; the other pastoral, seldom feeding on wild 

 animals, ignorant of the arrow and the Hint weapon, and which 

 used quartz, ophites, and other stones, but seldom Unit for making 

 axes. 



But litile .seems to have been done in the Botanical section, 

 one of the most valuali'.e papers having been that of M. Van 

 TiegheiTi, expounding the result of his researches into "Germina- 

 tion," which had for their object to determine experimentally the 

 connectim existing between the various organs of the embryo, 

 and the degree of dependence of the latter upon the albumen. 

 .\no;her elaborate paper was by M. Baillon, " On the Floral 

 Organ'sition of the Aiiieittaii\c, and especially the Hazel." 



Some of the most valuable and interesting papers of the meet- 

 ing were read in the Section of Physics ; the first, and one of 

 the most attractive, w.-s by M. A. Lallemanc?, President of the 

 Section, "On the Pohrisalion and Colouration of the Atmo- 

 sphere." The researches of M. Lallem.ard have been conducted 

 on the basis of a theory which explains at once the origin of 

 aerial polarisation, the formation of the neutral points indicated 

 by .\rago and Babinet, and the blue colour of the atmosphere. 

 According to him, atmospheric illumination is only a particular 

 ins ance of the phenomena of illumination of transparent bodies 

 by a pencil of non-polarised solar rays. The generation of 

 neutral points is explained simply by the intervention of the dust 

 and atmospheric corpuscles which abound in the lower layers 

 of the atmosphere, in the centre of which the observer finds 

 himself placed. This paper was followed by another by 

 M. .Soret, of Geneva, "On the Influence of the Atmo- 

 sphere upon the Intensity of Solar Radiation." The new 

 experiments of M. Soret have been made by means of two 

 calorimeters made upon the same principle and of analogous 

 construction. The first, which is described under the name 

 of "Actir.ometre Transportable," is of small size, and consists 

 simply of a metallic tube open at one end surrounded by a second 

 concentric envelope. The interval between the two is filled with 

 ice. At the bottom of the tube is fixed a thermometer, whose 

 stem ciosses the two envelopes, and upon which the sun's rays 

 are allowed to fall. The thermometer, zero at the outset, rises 

 in proportion as the quantity of heat which it receives equals 

 that which it loses by radiation. The temperature which it finally 

 reaches enables us to deduce the intensity of the solar radiation, 

 after a certain number of corrections, the principal of which relate 



to barometric pressure. The Fixed Actinome'er differs from the 

 preceding only in its greater size, which allows of four thermo- 

 meters being used instead of one : the inch)sed interval is niain- 

 lained at a constant temperature by a current of water. The 

 experiments made by means of these instruments have enabled 

 M. Suret to ascertain, in the first place, that the more moisture 

 there is in the air, the less is the intensity of solar radiation for 

 the .same height of the sun and the same atmospheric pressure. 



In the same section, M. Cornu presented a detailed sketch of 

 the dark rays in the ultra-vio'et part of tlie solar spectrum, fol- 

 lowing the scale of the wave lengths adopted by M. Angstrom 

 in his memoir on the normal spectrum of the sun. These 

 sketches have been made from the micrometric measurement to the 

 microscope of photographic plates, forming two series. The 

 first series has been obtained with the assistance of Noberc's net- 

 wo:k{of iSoi lines), of which the second spectrum was vety 

 perfect and very luminous ; the proof obtained contained the 

 rays G, Hj, H.^, L, JI, N, O, P, and even Q, although the ob- 

 ject glasses of Gonionde were of crown and flint glass. M. 

 Cornu has verified the correctness of the measures of M. JIascart ; 

 the comparison of the results has always shoAin four common 

 figures in the numerical expression of the wave-lengths. The 

 second series, intended to fumi;h details of the rays of the pho- 

 tograph, proceed from a spectrum much dispersed and of great 

 dehcacy ; more than twenty-five were c Hinted between the two 

 rays Hj H,. This spectrunr was obtained with a flint prism of 

 60*^ ; the moist collodion had taken an impression even up to the 

 ray O, in spite of the absorbing power of the two object-ghasses. 

 M. Cornu st-ongly recommends the use of these ordinary achro- 

 matic object-glasses for obtaining photographs of the ultra violet 

 region, when it is desired to go no farther than ray O ; the in- 

 convenience of the absorbing power is largely compensated for by 

 the ease of setting in posiiion and by the angular size of the 

 region where the lines are clearly distinguished. With regard to 

 the process itself, it differs but little from that o*" M. Mascart. 

 M. Cornu, however, advises the adoption of a small dark 

 chamber exterior to the telescoj e, in place of the photographic 

 camera of M. Ma«cart. The advantage of employii g collodion- 

 ised surfaces sufficiently large to make room lor the spots and 

 other defects, arises from the thinness of the plate. M. 

 Cornu further indicates upon his sketches the principal lines 

 of magnesium, lime, manganese, and iron, which, as is known, 

 compose the greater part of the groups, L, M, and N. 



M. Sain'-Loup followed with a paper on a proposed modifica- 

 tion of IIolz's machine. Other papers of interest in this depart- 

 ment were by M. Potier on " The Elliptical Polarisation pro- 

 duced by Vitreous Reflection ;" by M. Petit on a Modification 

 of the Ordinary Telegraphic Sjstem, by means of which the 

 telegraph may be madeto print directly ; .M. Descloizeaux a very 

 curious paper on some of the Optical Phenomena of Crystals ; 

 and M. Gariel on the Distribution of Magnetism in Magnets. 



In the Chemical Section, presided over by M. Balard, M. 

 Berthelot read a paper of considerable practical value "On the 

 State of Bodies held in Solution," in which he brought much 

 discrimination and research to bear upon some of the ordinary 

 problems of Ch;mistry, espec-ally upon molecular mechanics. 

 Other papers in this section were by M. Jungflcisch "Onihe 

 Transformation of Tartaric Acid into Racemic Acid," and by 

 M. Fdhol " On the Nature of the Sulphuric Composition of the 

 Mineral Waters of the Pyrenees." 



In the Section of Zoology, under M. Soubeirau, various in- 

 teresting papers were read, including one by M. Chatin, "On 

 the Odoriferous Glands of some Mammiferous Animals ;" one by 

 M. Jobert, " On the Organs of Touch in Fishes ; " one of con- 

 siderable interest by M. Soubeiran, on the Oyster Culture at 

 Arcachon ; and one by M. Pouchet on the Colourisation of 

 Fishes. 



The Geological Section was presided over by M. Raulin, Pro- 

 fessor at the Faculty of Sciences at Bordeaux, and in the section 

 devoted to Mathematics, Astronomy, f^eodesy, and Mechanics a 

 paper was read by Madame llureau de Villeneuve "On the 

 Mechanism of the Flying Apparatus of Biids." She was pre- 

 ceded by M. Respighi, who read an able paper on the Scintilla- 

 tion of .Stars. In accordance with a long series of observations 

 made by him, he showed that the changes in brightness and 

 colour presented by stars near the horizon are caused by momen- 

 tary and successive deviationsof luminous rays of different colours, 



