NATURE 



[June 19, 1 < 



illustrated by models, on the graphical representation of physical 

 properties ; and Mr. David Traill one on geometry from first 

 principles. 



Paris 



Academy of Sciences, June 9. — M. Rolland, president, in 

 the chair. — Remarks on the apparent contour of the planet 

 Venus, based on the study of the photographic plates obtained 

 at Puebla during the recent transit of Venus, by MM. Bouquet 

 de la Grye and Arago. — Note on heavy ordnance in connection 

 with the large gun (16 cm.) lately supplied to the Spanish 

 Government by the Societe des Forges et Chantiers de la 

 Mediterranee, by M. Dupuy de Lome. — Memoir on the presence 

 of manganese in plants and animals, and on the part played by 

 this substance in the animal system, by M. E. Maumene. Tea 

 and tobacco are found to contain the largest quantities of metallic 

 manganese, which is on the whole injurious to animals, and con- 

 stantly rejected by them, hence it should no longer be employed 

 medicinally. — On the aspect of Uranus and the inclination of its 

 equator, as observed at the Paris Observatory during the first 

 days of the present year, by MM. Paul and Prosper Henry. — 

 Note on the symmetrical functions of the differences in the 

 roots of an equation, by M. J. Tannery. — Description of a 

 dynamo-electric machine on a new principle, a model of which 

 has been constructed by MM. A. Damoiseau and G. Petitpont. 

 For this engine it is claimed that it does double the work of those 

 now in use. — On the property of silver to absorb oxygen gas at 

 high temperatures, by M. L. Troost. — Note on the action of the 

 sulphuret of copper on the sulphuret of potassium, by M. A. 

 Ditte. — On the solubility of the bromides, iodides, and chlorides 

 of potassium, sodium, calcium, and other halogenous salts, 

 by M. A. Etard. — Observations on some colloidal substances, 

 by M. E. Grimaux. — Synthesis of pyridic hydrides, results of 

 two years' researches with /3-lutidine and j8-collidine (boiling at 

 196 O), derivatives of cinchona and brucine, by M. Oechsner 

 de Coninck. These somewhat incomplete results are now pub- 

 lished in consequence of the remarkable facts recently disclosed 

 by MM. Hofmann and Ladenburg. — On tribenzoylmesitylene, 

 by M. E. Louise. — On crystallised colchicine, by M. A. 

 Houdes. — Experiments on manure artificially prepared with a 

 view to determining the amount of loss of nitrogen sustained 

 during the process of fermentation, by M. H. Joulie. The loss 

 of nitrogen was found to be about 20 per cent., a proportion 

 inferior to what takes place in practice. — Note on the minerals 

 associated with the diamond in the newly-discovered diamanti- 

 ferous district of Salobro, province of Bahia, Brazil, by M. H. 

 Gorceix. — Anatomy of the Echinoderms ; on the organisation of 

 the Comatules, by M. Edm. Perrier. — On the constitution of the 

 Echinoderms, by M. C. Viguier.— Objections to the theory that 

 the Sahara was a marine basin during the Quaternary period, by 

 M. G. Rolland. From more recent surveys in various parts of 

 this region the author concludes that since the Tertiary period 

 Ihe Sahara was mainly dry land, while at the close of the Mio- 

 cene all North Africa had been upheaved, and since then during 

 the Pliocene and Quaternary the South Mediterranean coast-line 

 has undergone no important modifications. — On the lesions of the 

 nerve-ducts of the spinal marrow in sclerotic affections, by M. 

 J. Babinski. — M. Jamin was elected Perpetual Secretary in the 

 Section of Physical Sciences in place of the late M. Dumas. 



Berlin 



Physical Society, May 23. — Prof. H. W. Vogel reported 

 on the final practical results of his researches conducted for many 

 years on the means of photographing coloured objects in their 

 natural shades. Sensitive plates arc known to be affected only 

 by the more refrangible rays, the less refrangible remaining in- 

 operative. Hence, of coloured objects quite unnatural pictures 

 are obtained, even the darkest shades of blue appearing as white ; 

 yellow and red, however bright and dazzling, as black ; and so 

 on Starting from the idea that the sensitive collodium is 

 affected only by such rays as are absorbed by it, Prof. Vogel had 

 years ago been occupied with the attempt to render his plates 

 sensitive to less refrangible rays, by alloying the silver coating 

 with a substance capable of absorbing these rays. The results 

 corresponded at once with this a priori assumption. In fact, 

 plates so prepared invariably produced an effect in the solar 

 spectrum wherever the absorption bands of the alloy were found. 

 It was impossible, however, to obtain like results with artificial 

 colours. Many colouring substances which, when blended with 

 the collodium, beautifully reproduced the yellow of the solar 



spectrum, were ineffective against the artificial and infinitely 

 fainter yellow of painters. Prof. Vogel was induced constantly 

 to resume these attempts by the progress made both in the pre- 

 paration of photographic appliances and in the discovery of new 

 organic substances possessing a power of absorption more intense 

 and lying nearer to the yellow of the spectrum. He has 

 thus at last succeeded in obtaining in eosine, and more 

 especially its various derivatives, colouring substances which 

 scarcely possess more than a broad absorption band in the 

 yellow, and which led to the desired result. When these 

 bodies were mixed in due proportion with the dry gelatine 

 plates, the yellow of the coloured objects already appeared quite 

 clear on the photograph ; but the blue was still always brighter. 

 No satisfactory result was obtained until Heir Vogel had in- 

 serted between the object and the camera a yellow glass, which 

 partly absorbs the blue rays while leaving the yellow unimpaired. 

 He now obtained photographs in which the blue, as well as the 

 green and yellow, and partly even the red parts of the coloured 

 objects, presented to the observer's eye the same vivid effects as 

 the original. A series of photographs exhibited by Herr Vogel 

 side by side with the original pictures attest the good results with 

 which this method may be carried out in practice. — Prof. Land- 

 olt referred to the controversy between MM. Pasteur and Jung- 

 fleisch. the former of whom had obtained from the optically inac- 

 tive racemic acid dextro-gyrate tartaric acid by the culture of Peni- 

 cillium. This he explained by supposing that the mould assimi- 

 lates the other constituent of the inactive racemic acid, that is, 

 the lsevo-gyrate tartaric acid, leaving the other constituent over, 

 whereas Mr. Jungfleisch accounts for the elimination of the dextro- 

 gyrate tartaric acid simply by its greater solubility. In support 

 of Pasteur's view Prof. Landolt now adduced the experiment 

 with amygdalic acid made last year by Dr. Lewkowitsch in his 

 laboratory. Inactive amygdalic acid was by him, also by means 

 of Penicillium, converted into dextro-gyrate amygdalic acid, which, 

 jointly with the lrevo-gyrate amygdalic acid formed from amyg- 

 daline, constituted inactive amygdalic acid, such as is obtained 

 from piussic acid. Herr Landolt further reported that in his 

 laboratory it had recently been demonstrated that tyrosine and 

 leucine are optically active. Hence, according to the still 

 unshaken theory of van t'Hoff, these substances must contain 

 unsymmetrically united atoms of carbon. 



CONTENTS Page 



The London Water Supply 165 



Flowers and their Pedigrees 167 



Our Book Shelf:— 



Herrick's " Wonders of Plant-Life " 168 



Waters' "Histological Notes for the Use of Medical 



Students " 168 



Letters to the Editor :— 



Pile-Dwellings on Hill-tops.— S. E. Peal. (Illus- 

 trated) 168 



Atmospheric Dust. — R. Brough Smith 170 



The " Red Glow " after Sunset.— Prof. J. P. 



O'Reilly 170 



The Earthquake.— R. McLachlan, F.R.S. ... 170 



Intelligence in Animals. — M 170 



Adolphe Wurtz and his Chemical Work. ( With 



Portrait) 170 



African Exploration. (With Map) 172 



A New Astronomical Journal 173 



Measuring Earthquakes, II. P.y Prof. J. A. Ewing. 



• (Illustrated) 174 



Notes on a Few of the Glaciers in the Main Strait 

 of Magellan made during the Summers of 1882-83 

 in H. M.S. "Sylvia." By Capt. W. J. L. Wharton, 

 R.N., Hydrographer to the Admiralty. (Illus- 

 trated) 177 



Notes 179 



Our Astronomical Column : — 



Recent Improvements in Astronomical Instruments . 181 



The Aspect of Uranus 1S2 



The Continuity of the Protoplasm through the Walls 



of Vegetable Cells 182 



National Work and Health 183 



University and Educational Intelligence 1S6 



Societies and Academies 186 



