March 



12, 



I903] 



NA TURE 



455 



graphy of opaque objects was not so easy as that of trans- 

 parent objects, for though the broad principles seemed very 

 simple, there were difficulties quite unknown to those who 

 only photographed transparent objects. He used a long 

 camera with powers from 6" up to ii", and had found the 

 incandescent gas light was the best light for the purpose. 

 Success entirely hinged upon obtaining a good contrast of 

 light and shade, and in addition to the difficulties in con- 

 nection therewith, a great obstacle arose from the inequality 

 of the surfaces of many objects, which rendered focusing 

 troublesome. 



Edinburgh. 



Royal Society, February 2. — Prof. James Geikie, F.R.S., 

 in the chair. — The meeting was devoted to papers giving 

 some of the preliminary results obtained last season during 

 the bathymetrical survey of the Scottish fresh-water lakes 

 under the direction of Sir John Murray, K.C.B., F.R.S. — 

 Dr. T. N. Johnston gave an account of Loch Morar and 

 the neighbouring lochs Beoraid and Nostarie, which drain 

 into it, showing that Loch Morar, with a maximum deptn 

 of 1009 feet, is the deepest known British lake. There are 

 seven European lakes known to be deeper, but only three 

 of these exceed it in depth below sea-level. At the time of 

 surveying, the surface of Loch Morar was found to be 3o'5 

 feet above sea-level, and its mean depth is calculated at 284 

 feet. Loch Beoraid has a maximum depth of 159 feet, and 

 its surface was found to be 170 feet above sea-level. Loch 

 Nostarie, with a maximum depth of 35 feet, is a shallow 

 loch lying in the drift at a height of 893 feet above sea- 

 level. — Mr. T. R. H. Garrett read a paper on the temper- 

 atures in Lochs Morar, Eilt and Dubh (Ailort). The depth 

 of Eilt is 119 feet, and that of Dubh is 153 feet, whilst their 

 heights above sea-level are 96 feet and 103 feet respectively. 

 The temperature in the western portion of Eilt was higher 

 at all depths than in the central, and higher in the central 

 than in the eastern ; this was attributed to the north-east 

 winds of the previous week. The temperature in Loch Dubh 

 on July 12, 1902, was 59°o at the surface and 43°'5 at the 

 bottom, which is the greatest range observed on any one 

 day in any Scottish loch during last year. This was 

 attributed to the small area of the loch compared with its 

 depth, and to its extremely small drainage area. He placed 

 the limit of penetration of heat due to solar radiation in Loch 

 Morar at 800 feet, and compared this limit with that of 300 

 to 450 feet in Lake Geneva as given by Forel. — Mr. James 

 Murray read a paper on the pelagic life in the lochs, and 

 gave a summary of the biological work done during the 

 season. Most of the Entomostraca and Rotifera, and all 

 the lower forms, were found to be very uniformly dis- 

 tributed. In the Calanidae two species of Diaptomus, viz. 

 D. Wierzyskii and D. laciniatus, were shown to be gener- 

 ally distributed in the north. In the large and deep lochs 

 such as Morar and Tay, only a few species of almost cos- 

 mopolitan distribution constitute the fauna of the open 

 water. In smaller lochs life is much more abundant. The 

 total absence of Daphnia from Loch Morar and some other 

 lochs might suggest an investigation into the composition 

 of the water and other conditions of these lochs. In regard 

 to the vertical migration of pelagic animals, it was found 

 on one occasion in Loch Treig that the Copepoda were 

 abundant at a depth of from 40 to 90 feet, but scarce 

 nearer the surface. Some curiosities of distribution were 

 given, such as the occurrence of great numbers of the 

 empty cases of Clathrulina in several large lochs, although 

 the animal was never found alive in any loch. 



Paris. 



Academy of Sciences, March 2. — M. Albert Gaudry in 

 the chair. — The storm of March 2, 1903, by M. Mascart. 

 Mention is made of the usefulness of the meteorological 

 station at the Azores. The barometer stood at 7 p.m. at 775 

 mm. at Horta, in the Azores, whilst in the north of Ireland 

 at the same time it was 725 mm., a gradient of 50 mm. 

 between the two stations, an altogether exceptional value, 

 and which fully explains the violence of the storm. — On the 

 absorption of light (1) by a body naturally heterotropic 

 and on which an intense magnetic field has impressed a 

 strong rotatory power, and (2) by an isotropic body, which 

 such a field renders both birefringent and asymmetric, by 

 M. J. Boussinesq. — The preparation and properties of two 



NO. 1 74 1, vol. 67] 



tetra-alkyl-diamido-diphenylanthrones, by MM. A. Haller 

 and A. Guyot. The tetramethyl-diamido-diphenylanthrone 

 is obtained in good yield by the condensation of the chloride 

 of anthraquinone with dimethyl-aniline in carbon bisulphide 

 solution in presence of aluminium chloride. The corre- 

 sponding ethyl compound is obtained in a similar manner, 

 diethyl-aniline being substituted for the dimethyl-aniline. 

 Both compounds react with dilute mineral acids to form 

 colourless salts. — On the generalisation of the Laplace-Abel 

 integral, by M. G. Mittag-Leffler. — The discovery of fishes 

 in the Devonian layer of the Pas-du-Calais, by M. J. 

 Gosselet. The fossils found were of the genus Pteraspis, 

 which is very common in the Old Red Sandstone in England 

 and Scotland, but which has not been previously found in the 

 Ardennes or in the eastern prolongations. — Remarks by 

 M. C. de Freycinet on the experimental teaching of geo- 

 metry. — Observations on the comet 1902 6, made with the 

 35 cm. equatorial of the Observatory of Lyons, by MM. J. 

 Guillaume and G. le Cadet. The comet had the aspect 

 of a very feeble nebulosity, which sometimes appeared to 

 show a faint condensation. It was at the limit of visibility 

 with the magnification of 150 employed for the measure- 

 ments. — Perturbations which do not depend on the elon- 

 gation, by M. Jean Mascart. — On slipping in fluids : a cor- 

 rection of a preceding note, by M. Hadamard. — Remarks 

 on the liquidogenic theories of fluids, by M. E. Mathias. 

 Of the two views of the phenomena at the critical point, 

 the one regards the saturated state as univariant, the 

 temperature determining the pressure as well as the density 

 of the saturated fluid. This leaves certain facts unexplained, 

 such as the anomalies between the densities of the liquid 

 and saturated vapour in Natterer's tubes, the disappearance 

 of the meniscus below the critical temperature, and the 

 possible heterogeneity of the fluid above the critical point. 

 These phenomena are explained by the theory of De Heen. 

 The author shows that these two theories are not necessarily 

 incompatible.— New researches on electric convection, by 

 MM. H. Pender and V. Cremieu. The authors, working 

 independently, have previously arrived at contradictory re- 

 sults on the magnetic effect of electric convection, and hence 

 have decided to pursue the subject in collaboration. So far 

 the experiments have given indecisive results, the effects 

 being very irregular. — On the heat of combustion of phos- 

 phorus and on the phosphoric anhydrides, by M. H. Giran. 

 The heat of combustion of yellow phosphorus has been deter- 

 mined by burning with compressed oxygen in the Mahler 

 bomb, the results being about 3 per cent, higher than those 

 currently accepted. From the heat of solution of the pent- 

 oxide obtained, it would appear to consist of the amorphous 

 variety. Metaphosphoric acid is the only product on solu- 

 tion in water. — On some new acetylenic acids, by MM. Ch. 

 Moureu and R. Delange. By acting upon acetylenes of 

 the general formula R — C=C — H with sodium and then 

 treating these with CO., the authors have prepared a number 

 of acetylene acids of the fatty series, the more important 

 physical properties of which are given. — Contribution to the 

 study of the thio-acids of the formula R — CO — SH, by MM. 

 V. Auger and M. Billy. The only method allowing of the 

 production of true thio-acids is that of K^kule, the saponi- 

 fication of esters with sodium hydrosulphide. — On para- 

 ethyl-benzoic aldehyde, by M. H. Fournier. An unsuc- 

 cessful attempt was made to prepare this aldehyde by the 

 action of hydrogen chloride and carbon monoxide on ethyl- 

 benzene in presence of aluminium chloride. It was obtained 

 by Bouveault's method by the action of ethoxalyl chloride 

 upon ethyl-benzene in presence of aluminium chloride, heat- 

 ing the resulting ester with aniline, and boiling the deri- 

 vative obtained with dilute sulphuric acid. — A method for 

 estimating glycerol in the blood, by M. Maurice Nicloux. 

 After precipitating and separating the albuminoid matters 

 of the blood, the glycerol is distilled in a vacuum at 100° C, 

 and estimated by potassium bichromate and sulphuric 

 acid. A series of test analyses is given, the mean error 

 being about 5 per cent., or approximately that inherent 

 in the bichromate method. — On the structure of the tracheal 

 cell of the gad-fly, and on the origin of the ergastoplasmic 

 formations, by MM. A. Conte and C. Vaney. — The mano- 

 metric ear, by M. Pierre Bonnier. A criticism of the re- 

 sults of experiments recently published by M. Marage. — The 

 nervous ganglia of the posterior roots belonging to the 

 system of the great sympathetic, by M. N. Alberto Barbieri. 



