July 14, 1904] 



NA TURE 



263 



nearly the atmosphere^ approximates to this condition. 

 Definition is often very good when gales are blowing, and 

 there is no doubt as to the better definition in summer than 

 in winter. These and other cases seem capable of e.xplan- 

 ation along the lines indicated. 



June 20. — The Hon. Lord M'Laren in the chair. — A 

 paper was communicated by Lord Kelvin on the front and 

 rear of a free procession of waves in deep water. A solu- 

 tion of the differential equations was obtained which re- 

 presented a set of standing waves on an infinite sheet of 

 water. At time ?ero this set of standing waves was con- 

 ceived as taking place over one-half, to the left (say) of a 

 line drawn parallel to the ridges, while the rest of the 

 surface to the right was initially at rest. The standing 

 waves were then decomposed into two equal processions 

 moving respectively to the right and to the left. At any 

 finite time after there would be a point to the right up 

 to which the motion would be sinusoidal, and beyond which, 

 further to the right, the waves would get flatter and longer. 

 This represented the beginning of a procession of waves 

 advancing into still water. Then to the left of the original 

 line separating the undulating and smooth water there 

 would be associated with the rightward moving procession 

 of sinusoidal waves the tail end of the leftward moving 

 procession. This would give the end of a procession of 

 waves. — Dr. Ashworth and Mr. Nelson Annandale gave 

 an account of some aged specimens of sea-anemone 

 (Sagartia troglodytes) which had been kept in an aquarium 

 in Edinburgh for about fifty years. They are more sensitive 

 than younger individuals to changes of environment, and 

 slower in e.xpanding when conditions again become favour- 

 able. They breed very sparingly, while the younger speci- 

 mens from fourteen to fifteen years old kept in the same 

 aquarium produce hundreds of young. There is only one 

 other recorded case of longevity in coelenterates, a speci- 

 men of the anemone Actinia mcsemhryaiithcmum, which 

 died in 1887 at the age of about si.\ty-si.\. .'\ccording to 

 unpublished observations of Mr. J. S. Gardiner, the solitary 

 coral Flahcllum rtibrtim lives to the age of twenty-four 

 years, while colonial corals, such as Goniastrsea, Prion- 

 astraea, Orbicella, and Pocillopora, reach the age of twenty- 

 two to twenty-eight years. — In a note on the effect of 

 transverse magnetisation on the resistance of nickel wire at 

 high temperatures. Prof. C. G. Knott described a curious 

 result recently obtained. The effect of a strong transverse 

 field is to diminish the resistance, and as the temperature 

 rises the percentage change of resistance falls off very 

 steadily until 280° C. is reached. It begins then to fall off 

 more slowly, passes through a pronounced minimum at 

 about 2go°, rises to a sharp maximum at 320°, and then 

 falls rapidly to zero at about 346°. A similar effect, but 

 much less pronounced, is indicated in the author's last pub- 

 lished paper on the effect of longitudinal magnetisation. 

 — Mr. J. R. Milne exhibited his new design of juxtapositer 

 for bringing into contact two beams of light in spectro- 

 photometry. The instrument had been made for him by 

 Mr. Hilger, and consisted of a special form of glass prism 

 by means of which two beams of light originally apart 

 were brought accurately with their contiguous edges in 

 contact, each be;im having been subjected to exactly the 

 same treatment in the prism. The device could also be 

 adapted to certain forms of polarimeter. 



Dublin. 

 Royal Dublin Society, June 21. — Prof G. A. J. Cole in 

 the chair. — .A general method in qualitative analysis for 

 determining the presence of an o.xide : Prof. C. R. C. 

 Tichborne. The author proposed to use the reaction of 

 phenol-phthalein with acid-carbonate of sodium. Phenol- 

 phlhalein is colourless in neutral solutions, red with alkaline 

 carbonates, and colourless with acid-carbonates. Most 

 metallic oxides will reduce a certain proportion of the acid- 

 carbonate to the normal carbonate, and the solution then 

 strikes a deep crimson colour if filtered from the oxide and 

 tested with the phenolphthalein. Almost all hydrated 

 oxides and oxides made in the moist way decompose the 

 sodium acid-carbonate solution. Mineral oxides or oxides 

 which have been ignited, with a few exceptions, behave 

 badly in this respect. Ferric oxide and alumina do not 

 act, as the carbonates do not exist. The following oxides 



NO. 181 I, VOL. 70] 



will reduce the acid carbonate to the neutral salt of soda : — 

 oxides of lead, silver, bismuth, zinc (ignited and pre- 

 cipitated), copper, antimony, cerium, iron (other than 

 Fe^Oj), mercury, and tin. — A method for the mechanical 

 analysis of soils : T. Crook. The method described is a 

 hydraulic one, and may be regarded as a modification of 

 the Schbne process. No piezometer is used, and the speeds 

 of flow are standardised by varying the size of the outflow 

 aperture and the head of water. The scheme of analysis 

 suggested is a fairly complete one, including the coarser 

 ingredients, as well as the fine earth. The author urges 

 that the object of a mechanical analysis should be two- 

 fold : — (i) to enable a moderately definite idea to be formed 

 of the way in which a soil is built up in its natural state; 

 (2) to show something of the physical properties possessed 

 by the soil. — The state in which helium exists in pitch- 

 blende : R. J. Moss. When pitchblende is reduced to 

 powder in a vacuum, water vapour, helium, carbon dioxide, 

 nitrogen, and oxygen are liberated. Water is the chief 

 substance set free ; of the gases, helium sometimes con- 

 stitutes about half. The helium obtained by rather coarse 

 pulverisation was about i per cent, of the total quantity 

 present in the mineral, as determined by fusion with 

 hydrogen potassium sulphate. The carbon dioxide obtained 

 mechanically was less than i part in 10,000 of the total 

 quantity present. The results support the supposition that 

 helium exists in pitchblende in the free state, and is con- 

 tained in extremely minute cavities. A specimen of pitch- 

 blende, powdered in vacuo, yielded gases containing 07 per 

 cent, of hydrogen, which may possibly be a product of the 

 action of radium on the water contained in the cavities of 

 the mineral. — The Rev. H. O'Toole exhibited and de- 

 scribed an apparatus for determining the expansion of rods, 

 &c., when heated. 



Paris. 

 Academy of Sciences, July 4.— M. Mascart in the chair. — 

 On certain lunctional equations and on a class of algebraic 

 surfaces : Emile Picard. — Syntheses in the anthracene 

 series. Triphenylanthracene dihydride and its derivatives : 

 A. Haller and A. Guyot. Two modes of synthesis are 

 given, the one starting from diphenylanthrone and the 

 other from triphenylmethane-o-carboxylic acid methyl ester, 

 making use of the Grignard reaction. Both give good 

 yields. — Muscular work and expenditure of energy in 

 dynamic contraction, with gradual shortening of the 

 muscles : A. Chauveau. — Trypanroth in the treatment of 

 trypanosomiasis : A. Laveran. The use of this dye was 

 proposed by Ehrlich and Shiga. The effects produced by 

 this reagent are compared wit:i those of arsenious acid ; 

 the tw-o have also been tried in combination, but the 

 general results are disappointing. — On the properties of 

 different substances as regards their ponderable emanation : 

 R. Blondlot. — On the seeds of Nevropteris : M. 

 Grand'Eury. — Presentation of the fifteenth Bulletin chrono- 

 nielriquc (1902-1903) of the Observatory of Besan^on : 

 ^L LcBwy. — M. Fliche was elected a correspondant of the 

 academy in the section of rural economy, in the place of 

 M. Lechartier. — On functions representable analytically : 

 H. Lebessue. — On the general theory of networks and 

 congruences : Emile Martin, — On a general equality com- 

 mon to all fundamental functions : W. Stekloff. — On the 

 stability of aerostats : Henri Herve. Comparative effects 

 of the 3-rays and the n-rays, as well as of the a-rays and 

 the n,-rays, on a phosphorescent surface : Jean Becquerel. 

 The radiations emitted by polonium affect a phos- 

 phorescent calcium sulphide screen, the action differing 

 according as the radiation has passed through glass or 

 not. — On the kathode rays. A reply to the note of M. 

 Pellat : P. Villard. — On the measurement of temperature : 

 Ernest Solvay. If two portions of a substance situated 

 near to each other have widely differing temperatures, it 

 is impossible to measure this difference with a liiermo- 

 meter, and a possible case of this kind is given. — On the 

 spectrophotometric estimation of small quantities of carbon 

 monoxide in air : L. de Saint-Martin. The instrument 

 measures the ratio between the amounts of haemoglobin 

 combined with oxygen and carbon monoxide, up to the 

 limit of 1 per cent, of CO. — The determination of the 

 atomic weight of nitrogen by the volumetric analysis of 

 nitrogen monoxide : .Adrien Jacquerod and St. Bogdan. 



