i66 



NA TURE 



[December 14, 1899 



young cells, and that the over-turgescence is expressed in the 

 abnormal protrusions. Hence the application of the name 

 "Intumescences." — Note on the name Balanoolosstis, by Dr. 

 Harmer. It was suggested that the species which belong to 

 Balanoglossus as restricted by Spengel should be placed in a new 

 genus Balanocephalus , whose type-species would be B. kupfferi. 

 Balanoglossus should be dropped as a generic name, but may 

 conveniently be retained as a semi-popular designation in cases 

 where it is not desired to restrict a statement to any particular 

 genus of the Enteropneusta. — The skeleton of Ash-osckra com- 

 pared with that of the Pharetronid sponges, by J. J. Lister. The 

 structure of Aslrosclera willeyana, the representative of a new 

 family of sponges, obtained by Dr. Willey in the Loyalty Islands, 

 was described, and attention was drawn to the resemblance 

 between its skeleton and that of some members of the Fhare- 

 trones, a group of sponges which are found as fossils in formations 

 ranging from the Carboniferous to the Cretaceous period. It was 

 pointed out that the resemblance between the skeletal elements 

 formed within the living protoplasm of Aslrosclera and the bodies 

 formed by purely physical processes in the St. Cassian fossils may 

 have a bearing on the problem of the mode of origin of sponge 

 spicules. — Note on hypotheses as to the origin of the paired 

 limbs of Vertebrates, by J. Graham Kerr. In a paper on 

 hypotheses as to the origin of the paired limbs of Vertebrates, 

 which was taken as read, Mr. J. Graham Kerr referred first to 

 the two hypotheses which were predominant at the present time 

 as explaining the origin of the paired limbs — that which derives 

 them from portions of a once continuous lateral finfold, and that 

 which derives them from the septa between adjacent gill-clefts. 

 The first portion of the paper consisted of a brief statement of 

 these two views together wiih the fundamental facts upon which 

 they rest, followed by a critical examination of them in the light 

 of modern research. The author came to the conclusion that 

 both views must be looked upon rather as suggestive hypotheses 

 than as scientific theories of the facts as at present known to us. 

 He therefore ventured to bring forward a third view, confessedly 

 a mere hypothesis, which seemed to him to have received very 

 inadequate attention — that the paired limbs are homodynamous 

 with the somatic or true external gills. — Observations upon 

 Polypterus and Protopterus, by J. S. Budgett. Two distinct 

 species of Polypterus occur in the Gambia, Polypterus lapradii 

 and Polypterus senegalus ; the latter was observed in captivity 

 and also in the wild state. The pectoral fins are distinctly organs 

 of propulsion and not as in Teleosts almost exclusively balancers. 

 Polypteros uses its bilobed air bladder as a lung, and can survive 

 an exposure to a damp atmosphere of twenty-four hours. The 

 spiracle is used to emit the excess of air in the pharynx but not 

 for the passage of water. Both species migrate from the river 

 to the flooded meadows in June and July and, spawning in 

 August and September, return to the river in October and 

 November. 



Edinburgh. 

 Royal Society, December 4. — Lord Kelvin in the chair. 

 As usual at the first meeting of the session, the President gave 

 a brief sketch of the work accomplished last session. Lord 

 Kelvin then proceeded to discuss two physical problems, 

 namely, the problem of the spinning top, and the question as to 

 the manner in which ether is affected by the motion through it 

 of attracting and repelling points. Many mathematicians of 

 the highest order had attacked the problem of the rotation of a 

 rigid body of which one point is fixed ; but the peculiarity of 

 the spinning top was that no point was fixed until it settled 

 into the so-called " sleeping " condition. Mr. Archibald Smith, 

 in a paper published in the first volume of the Cambridge Math. 

 fourn. (1837), seems to have been the first to have correctly 

 considered the question, Why does a spinning top rise to the 

 sleeping state and then fall away again ? And no later mathe- 

 matician seems to have taken up this question at all. Lord 

 Kelvin had recently worked out a simple case in which the 

 centre of gravity was constrained to move in a vertical line. 

 The minimum angular velocity, for which the upright " sleep- 

 ing " motion was stable, depended in a simple way upon the 

 curvature of the assumed hemispherical apex on which the top 

 spun. The second problem was a fresh attempt to reconcile 

 the apparently opposite properties of ether which render it so 

 mobile to mass motions through it and yet so sensitive to rapid 

 molecular vibrations. Briefly stated, the idea was to have an 

 intermediate link between the molecule and ether in the form 

 of a "doublet feeler." This doublet consisted of repelling and 

 attracting points, which produced appropriate strains in the 



NO. 1572, VOL. 61] 



ether when themselves set in vibration by the vibrating molecule. 

 The idea, however, gave no clue as to the nature of electricity 

 and magnetism. — In a paper on the rectal gland of the Elasmo- 

 branchs, Dr. J. Craw ford;j gave an account of an investigation 

 into the structure and function of this appendage in the dog-fish 

 and skate. The evidence was in favour of its being an excretory 

 organ of the nature of a kidney. — An obituary notice of Dr. 

 Charles Hayes Higgins. prepared by Dr. Sydney Marsden, was 

 read — Dr. Noel Paton gave an account of further investiga- 

 tions of the life history of the salmon in fresh water. This 

 second instalment dealt chiefly with the fish taken in the 

 months February, March and April, and the general conclu- 

 sions agreed with those already drawn, the chief result being 

 that the migration of the salmon is regulated wholly by the 

 question of nutrition. The comparative scarcity of male fish 

 caught prevented any certain conclusions being drawn in regard 

 to them. From a comparative study of the pigments Miss 

 Newbiggin had collected strong evidence in favour of Sir John 

 Murray's view that the colour of the salmon was derived from 

 the pigments in the Crustacea, which supplied directly or in- 

 directly the chief food for these fish. — Dr. Thomas Muir com- 

 municated a paper on the eliminant of a set of general ternary 

 quadrics. Part ii. 



Mathematical Society, December 8. — Mr. R. F. Muir- 

 head. President, in the chair. The following papers were 

 read : — On the evaluation of a certain determinant, by Prof. 

 Crawford. — A special case of the dissection of any two triangles 

 into mutually similar pairs of triangles, by Mr. Alex. D. 

 Russell. —Elementary proof of the potential theorems regarding 

 uniform spherical shells, by Dr, Peddie. 



Paris. 



Academy of Sciences, December 4. — M. van Tieghem in 

 the chair. Justification of Fermat's principle on the economy of 

 time in the transmission of a luminous movement through a 

 heterogeneous transparent isotropic medium, by M. J. Bou.ssi- 

 nesq. Researches on the phenomena of phosphorescence pro- 

 duced by the radiation of radium, by M. Henri Becquerel. The 

 rays given off" by some milligrams of barium chloride containing 

 radium were allowed to fall upon various substances, such as 

 calcium and strontium sulphides, rubies, diamond, calc spar, 

 fluorite, and hexagonal blende, in a Becquerel phosphoroscope. 

 When placed first in the dark, and then brought up to within 

 a few millimetres of the radiating substance, all those minerals 

 which became luminous under the influence of the X-rays, also 

 became luminous under the radium rays ; hut ruby and calc spar, 

 which only become phosphorescent under luminous rays, re- 

 mained dark. There are, however, differences between the 

 X-rays and these new radiations. Thus a specimen of diamond 

 which was brilliantly luminous under the action of radium 

 did not become luminous when exposed to the radiation from a 

 focus tube, and similar differences were noted for other sub- 

 stances. The whole of the facts observed show that there is 

 really a continuous giving out of energy by radio-active bodies. 

 — On the metallic compound radicals : mercury derivatives, by 

 M. Berthelot. Measurements of the heat of combustion and 

 formation of mercury-methyl, mercury-ethyl, and mercury- 

 phenyl.— Lactic acid, by MM. Berthelot and Delepine. A 

 thermochemical study of lactic acid, and lactones derived from 

 it. — On the explosion of potassium chlorate, by M. Berthelot. 

 If potassium chlorate is introduced suddenly into a vessel which 

 has been previously heated to a temperature much above that at 

 which decomposition commences, an explosion takes place, as 

 with picric acid under similar conditions, although under a slow 

 heating potassium chlorate shows no explosive properties. The 

 explosion produced is clear and sharp, although a little pro- 

 longed, resembling a slow powder. These facts give a 

 probable explanation of the recent explosion of chlorate at St. 

 Helens. — On the normal existence of arsenic in animals, and 

 its localisation in certain organs, by M. Armand Gautier. From 

 a consideration of the use of arsenical compounds as a specific 

 in certain diseases, especially in anaemia and Basedow's disease, 

 the author came to the conclusion that the activity of arsenic 

 in such diseases must be to its forming a constituent part of 

 some organs, more particularly the thyroid gland. A search 

 for arsenic showed that it is present as a normal constituent of 

 the thyroid gland in weighable amounts in herbivora, carnivora, 

 and in man. It is also present in smaller quantities in some 

 other organs. In the normal state, there would appear to 



