May 25, 1905] 



NA TURE 



95 



no decline in the small amount of base they contain, 

 although nitrification is always going on and requires a 

 supply of base from the soil. The authors show, from 

 rxperiments with water cultures and from a consideration 

 of the analyses of field crops, that the growing plant 

 withdraws more acid than base from the neutral salts 

 dissolved in the soil water, leaving behind a basic residue 

 in the form of bicarbonate. Calcium oxalate and other 

 organic salts in plant residues are converted by bacterial 

 action in the soil into calcium carbonate. These two 

 agencies restore bases to the soil in quantities approxi- 

 mately equivalent to their removal by nitrification, and so 

 maintain a neutral reaction in the soil. 



Zoological Society, May 2. — Dr. W. T. Blanford, 

 F.R.S., vice-president, in the chair. — Specimens of domestic 

 chicks to illustrate peculiarities in the hereditary trans- 

 mission of white plumage : W. Bateson. — On Leuco- 

 solenia contorta (Bowerbank), Ascaudra contorta (Haeckel), 

 and Ascetta spinosa (Lendenfeld) : Prof. E. A. Minchin. 

 The author pointed out that the nomenclature of the 

 Calcarea Homocoela was in a more tangled state than that 

 of any other group of the animal kingdom, with, perhaps, 

 the e.xception of the malarial parasites. Dr. Bowerbank, 

 who founded the species, gave a diagnosis that would fit 

 any Ascon, and his type specimens were jumbles of three 

 or four species ; consequently Prof. Minchin declared his 

 name to be of no systematic value whatever. To Haeckel's 

 name Ascandra contorta, Prof. Minchin referred a sponge 

 extremely abundant on the Mediterranean coasts of France. 

 Prof. Minchin preferred to name Ascandra contorta, H., as 

 Clathrina contorta. He believed that the Ascetta spinosa 

 was only an age variation of Clathrina contorta, not yet 

 possessing monaxon spicules. — Anatomy of the ferret- 

 liadger (Helictis personata), based on a dissection of a 

 specimen that had recently died in the society's gardens : 

 F. E. Beddard. — The osteology of the Eurylasmidje, and 

 the question of the systematic position of this group : 

 W. I'. Pycraft. While agreeing with the general con- 

 sensus of opinion as to the primitive character of these 

 birds, the author held that the isolated position which they 

 were supposed to occupy with regard to the remaining 

 Passeres was by no means justified by facts. The ptery- 

 lography, osteology, and myology of the Eurylsemidte all 

 tended to show that the nearest allies of these birds were 

 the Cotingidae. Although undoubtedly primitive, the group, 

 Mr. Pycraft pointed out, presented a number of specialised 

 characters, w'hich were especially marked in the skull and 

 muscles of the wing. 



Entomological Society, May 3. — Mr. F. Merrifield, 

 president, in the chair. — A series of Xenarthra ccvvicornis, 

 Baly; from Ceylon, illustrating the curious structure of 

 the antennae of the c? : M. Jacoby. — Specimens of 

 Tephrosia consonaria, ab. nigra, and melanic examples of 

 Boarmia consortaria, all from a wood in west Kent : G. T. 

 Porritt. These forms were exactly on the same lines as 

 the melanism in west Yorkshire, and it is curious they 

 should occur in such w-idely separate localities. The two 

 genera, however, are evidently prone to melanism, as Mr. 

 Porritt had now seen black, or almost black, specimens 

 of all the British species except Tephrosia punctidata. — 

 (i) Two specimens of the very rare Staphylinid, Mcclon 

 castaneus, Grav., taken in the Oxford district during the 

 last week of April ; (2) several examples of both se.xes of 

 the giant flea Hystrichopsylla talpae, Curtis, from field- 

 mouse nests in the same district ; (3) the type-specimen of 

 the Bostrichid beetle Dinoderus ocellaris, Steph. (taken by 

 the late Prof. Westwood at " Little Chelsea " previous to 

 1S30), from the Hope collection at Oxford : Commander 

 J. J. Walker. — Heliotropism in Pararge and Pyrameis : 

 Dr. G. B. Longrstafr. — The structure and life-history of 

 Psychoda scxpunctata, Curtis : J. A. Dell.— The three- 

 colour process as applied to insect photography : Dr. D. H. 

 Hutchinson. 



Mathematical Society, May 11. — Prof. Forsyth, presi- 

 dent, in the chair. — The following papers were communi- 

 cated : — The intersection of two conic sections : J. A. H. 

 Johnston. The object of the paper is to determine the 

 number (o, 2, or 4) of the real intersections of two real 

 conies by means of formulae involving the invariants, or 

 other concomitants of the svstem. The discrimination 



NO. 1856, VOL. 72] 



depends upon the signs of the coeflicients of a certain cubic 

 equation, one root of which can be interpreted, when all 

 the intersections are real, as the area of the quadrilateral 

 formed by them. It is shown that one of the conditions 

 of reality obtained by previous writers admits of very great 

 simplification. — On a system of conies yielding operators 

 which annihilate a cubic, and its bearing on the reduction 

 of the cubic to a sum of four cubes : H. G. Dawson. — 

 Informal communications were made as follows : — High 

 Pellian factorisations : Lieut. -Colonel A. Cunningham. 

 A method was explained for constructing very large 

 factorisable numbers of the form y^-|-i (with complete 

 resolution into prime factors) from the Pellian equation 

 v' — D.t-= — I. Examples were given, among them being 

 a number of 78 digits, viz. (2'"*-f3.2")--|-i ; this was 

 shown to be expressible as (2'''-f i) (2*''-t- 1)", for which the 

 resolution of the factors 2'''-)-i and 2'°-|-i had been 

 obtained by Lucas. — The stability of a loaded column : 

 Prof. A. E. H. Love. When the column can be treated 

 as a " thin " rod, and the contraction of the longitudinal 

 filaments is taken into account, the critical length is 

 slightly greater than that obtained by the ordinary method, 

 due to Euler, in which this contraction is neglected. The 

 correction of the critical length is found to be jTrfe, where 

 k is the radius of gyration of the cross-section of the 

 column about an axis through its ccntroid at right angles 

 to the plane of bending. 



Paris. 

 Academy of Sciences, May 15. — M. Troost in the chair.— 

 The president announced the death of M. Potier, member 

 of the section of physics. — The permeability of glass 

 vessels : M. Berthelot (see p. 88). — The propagation of 

 musical sounds in a tube of 3 metres diameter : J. Violle 

 and Th. Vautier. Notes of low pitch carry much better 

 than those of high pitch, the distance at which the sound 

 ceases to be clearly a musical note being inversely as the 

 square root of the number of vibrations, this result being 

 in accord with the theoretical investigations of Lord Ray- 

 leigh. From a large number of observations the con- 

 clusion is drawn that the velocity of sounds of different 

 pitch is the same to an accuracy of i part in 1000. — 

 On the menthones and menthols obtained by the reduction 

 of pulegone by the catalytic action of reduced nickel : 

 .\. Haller and C. Martine. Pulegomenthone was obtained 

 when the nickel was maintained at 140° to 160° C. ; its 

 physical and chemical properties are given, and there is 

 reason to suppose that the ketone obtained is a mixture 

 of menthones, and further work is being carried out in 

 this direction. By slightly modifying the conditions of the 

 reduction an additional pair of hydrogen atoms is taken 

 up, giving pulegomenthols, two of which, in addition to 

 ordinary menthol, were isolated from the product of the 

 reduction. — On the constitution, saccharification, and re- 

 trogradation of potato starch : L. Maquenne and Eug. 

 Roux. Natural starch is regarded by the authors as a 

 mixture of two substances, distinguished by the names 

 amylocellulose and amylopectine, possessing different re- 

 actions towards iodine and malt extract. — The basic mag- 

 nesium carbonates from the Santorin eruption of 1866 : A. 

 Lacroix. The structure of this mineral, the quantities of 

 which were too small for quantitative analysis, agrees w-ith 

 that of the basic carbonate 4MgCO,,.Mg(bH).,.4H,0. As 

 this appears to be a new species, the name of giorgiosite 

 is proposed for it. — On the lifting power of a motor-driven 

 helix : Prince of Monaco. — M. Louis Henry was elected 

 a correspondant for the section of chemistry in the place 

 of Prof. Williamson. — On a photographic meridian tele- 

 scope for determining right ascension : Jean Mascart and 

 W. Ebert. — On the forces giving rise to conical trajec- 

 tories : Cyparissos Stephanos. — On the electrostatic 

 rigidity of gases at high pressures : Ch. Eug. Guye and 

 H. Guye. Measurements were made of the explosive 

 potential in gases at varying pressures. The gases studied 

 were nitrogen, air, o.xygen, hydrogen, and carbon dioxide, 

 the pressures varying from 2 to 65 metres of mercury. 

 Lip to 10 atmospheres, the explosive potential is a linear 

 function of the pressure, but for higher pressures the ratio 

 of explosive potential to pressure diminishes. The results 

 were unaffected by the presence of a radium salt. — On the 

 effects of Foucault currents and the hysteresis of iron on 

 oscillatory sparks : G. A. Hemsalech. By means of a 



