February 22, 1900] 



NATURE 



407 



beetles stridulate was apparently known to Darwin, who, in the 

 " Descent of Man," erroneously stated that thestridulating area 

 was situated on the pygidium. 



Dublin. 

 Royal Irish Academy, February 12.— Dr. Benjamin 

 Williamson, F.R.S., Vice-President, in the chair. — Prof. Charles 

 J. Joly read a paper on the place of the Ausdehnungskhre in 

 the general associative algebra of the Quaternion type. He 

 pointed out that the cardinal distinction between quaternions 

 and other systems of space analysis lies in the thoroughly 

 associative and distributive character of the former. He showed 

 that a Cirassmann system applicable to a space of n dimensions 

 is equivalent to a very restricted use of the associative algebra 

 of «+l units obeying the laws /.'■^= - i, and i,if\-iti, — o. In 

 fact, a progressive product is simply the part of highest order 

 in the units in a complete product in the associative algebra. 

 Regressive products are formed by the simple artifice of 

 dividing "products" of order «+i by the product of all the 

 units, and then starting afresh. The point symbol may be con- 

 sidered to be introduced by the artifice of leaving the origin 

 arbitrary exactly as Hamilton has done, but somewhere in the 

 fourth dimension when dealing with Euclidian space. — Prof. 

 Grenviile A. J. Cole read a paper on metamorphic rocks in 

 eastern Tyrone and southern Donegal. The gneissic axis north 

 of Pomeroy is shown in this paper to be invaded by granite of 

 the Slieve Gallion type, and the metamorphism of the central 

 region thus occurred, in all probability, prior to the "Cale- 

 donian " earth-movements. The gneiss itself, however, rarely 

 shows the effects of pressure, and its structures seem due to the 

 invasion of basic schists by an aplitic granite at some early 

 period. Direct comparison is made between its structures and 

 those that are clearly due to the invasion of the Slieve Gallion 

 granite into schists at Fir Mountain. The large area west of 

 Pettigo in South Donegal similarly shows a foliated granite (the 

 archaean gneiss), which owes most of its foliation to the inclusion 

 and streaking out of masses of pre-existing amphibolite. 

 Bands of micaceous rock are formed from the partial absorption 

 and metamorphism of garnet- pyroxenites and garnet-amphi- 

 bolites. The latter rocks may bave been sedimentary, and are 

 now found as great ' ' eyes " and lenticles, round which the pure 

 white gneiss flows, and into which it sends off veins. The 

 boundary between the Dalradian schists and the gneiss is suffi- 

 ciently obscure in this area for it to be possible that the amphi- 

 bolites were originally the lower members of the Dalradian 

 series. At any rate, they represent a floor on which the Dal- 

 radians were laid down. The gneiss is in no sense the funda- 

 mental rock ; it is, however, traversed by later granite veins, 

 which belong proliably to the Caledonian intrusions. As in 

 some French districts, the metamorphic area of South Donegal 

 shows the effects of igneous intrusion and contact-metamor- 

 phism on a regional scale, and dynamic metamorphism has 

 played but a minor part in determining its structures. 



Paris. 

 Academy of Sciences, February 12.— M. Maurice Levy in 

 the chair. — The President announced, to the Academy the loss 

 it had sustained by the death of M. P2mile Blanchard, member 

 of the Section of Anatomy and Zoology. — Researches in the 

 uric acid series, by M. Berthelot. Determination of the heats 

 of combustion and formation of methyl purine, hypoxanthine, 

 8-oxypurin, and 7-methylhypoxanthine. — On the dispersion of 

 the radium rays in a magnetic field, by M. Henri Becquerel. A 

 continuation of work previously published upon the same sub- 

 ject. The experiments were carried out in a uniform magnetic 

 field, of intensity H, and the radius of curvature, p, of the path 

 of the ray measured, Hp being constant. The lower limit of 

 Hp was measured when screens of various substances (paper, 

 aluminium, mica, glass, platinum, &c. ) were interposed. Some 

 of the phenomena observed are not capable of explanation by 

 any simple hypothesis. — The synthesis of campholic acid by 

 means of camphoric acid, by MM. A. Haller and G. Blanc. 

 The steps of the synthesis are as follows : camphor is oxidised 

 to camphoric acid, and this reduced with sodium amalgam to 

 <;ampholide. This, by treatment with hydrobromic acid and 

 subsequent reduction, yields campholic acid.— M. Schwendener 

 was elected a correspondant for the Section of Botany, in the 

 place of the late Baron de Muller.— Rapid variations of radial 

 velocity of the star 5-Orion, by M. H. Deslandres. Eleven 

 photographs of the spectrum of S-Orion is taken between December 

 8, 1899, and January 25, 1900, showed that this star possesses 



NO. 1582, VOL. 61] 



periodic variations in its radial velocity, the period being about 

 I '92 days. — The dynamical laws of ^clones, by M. Admiral 

 Fournier. The author deduces an expression correlating the 

 barometric pressures at two points, and the corresponding dis- 

 tances from the centre of the cyclone, which will be of practical 

 service in navigation. — On the tangent circles to four isotropic 

 planes ; and on surfaces of double circular generation, by M. 

 Eugene Casserat. — On harmonic equations and isothermal 

 surfaces, by M. A. Thybaut. — On anharmonic algebraic equa- 

 tions, by M. Autonne. — Plausible value of a variable magnitude, 

 by M. Estienne. — On two problems in probability, by M. 

 Andrade. A rectification of a note previously published. — On 

 the method of Neumann and Dirichlet's problem, by M, 

 W. Stekloff. — On the zeros of real integrals of linear 

 equations of the third order, by M. Davidoglou. — On 

 the constitution of white light, by M. E. Carvallo. A reply 

 to the criticism of M. Gouy. — On some consequences of the 

 prism formulae, by M. A. de Gramont. — A new source of light 

 for spectrometry of precision, by MM. Ch. Fabry and A. Perot. 

 An arc is formed between two metallic poles, one of which is 

 kept in rapid oscillation, the whole apparatus being in vacuo. 

 The troubles incident to the production of a continuous arc in a 

 vacuum are overcome by the device of keeping one pole in 

 oscillation. — ^A comparison of various patterns of the Wehnelt 

 contact-breaker, by M. Alfred Turpain. From the point of 

 view of duration and economy, the form with holes suggested 

 by Caldwell is preferable to the form with platinum wire. For 

 usefulness and rapidity either pattern of Wehnelt interrupter is 

 better than the Foucault contact-breaker. — On thermomagnetic 

 currents, by M. G. Moreau. The author regards his experi- 

 ments as proving that the Hall phenomenon is due to a deform- 

 ation of the plate under the influence of the magnetic field. — 

 Complete synthesis of the phorone of camphoric acid, by M. L. 

 Bouveault. From adipic acid a-methylcyclopentanone is pre- 

 pared, and this, condensed with acetone, gives the phorone of 

 camphoric acid. — On the composition of essence of sandal wood 

 from the East Indies, by M. M. Guerbet. Two isomeric hydro- 

 carbons were isolated, each of the «omposition CijH,^, and 

 distinguished as a- and /Ssantalene. A mixture of alcohols 

 C]gH240, an aldehyde, santalal, and two acids were also 

 obtained, further investigations on which will be proceeded 

 with. — Transformation of nitrobenzene into aniline by an organic 

 reducing ferment, by MM. E. Abelous and E. Gerard. The 

 ferment present in the kidney of the horse, which in previous 

 papers has been shown to be capable of reducing nitrates to 

 fiitrites, is now found to reduce nitrobenzene to aniline.— 

 Researches on the digestion of the reserves in seeds in the course 

 of germination, and their assimilation by the young plant, by M. 

 Maze. Seeds containing oil are capable of transforming the 

 group CH2 into an alcoholic group CH(OH) by taking up oxygen 

 from the air. — New researches on the evolution of the mon- 

 strillids, by M. A. Malaquin. — On a form of optically negative 

 anhydrous silica, by M. A. Lacroix. The mineral described 

 consists of anhydrous silica containing a little opal, and is found 

 in widely differing strata. Its density is about 2-5 ; it is biaxial 

 and optically negative. It is clearly differentiated from quart- 

 zine, lutecite and chalcedony, and it is proposed to name it 

 pseudo-chalcedonite. — On some granitic rocks of Cape Marsa, 

 by MM. L. Duparc and F. Pearce. — Examination of a meteorite 

 which fell at Bierbele, near Borgo, in Finland, on March 12, 

 1899, by M. Stanislas Meunier. — Specific heats of some organic 

 substances, by M. G. Fleury. The specific heats of cellulose, 

 wool and leather are given. 



Amsterdam. 

 Royal Academy of Sciences, December 30, 1899. — 

 Prof. Stokvis in the chair. — Report by Prof. Martin and Prof. 

 Behrens on the paper, presented by Dr. H. van Cappelle, 

 entitled " New observations on the Dutch dilivium, especially 

 with a view to mapping out this formation (II.)." The con- 

 clusion arrived at, viz. to insert this paper in the Transactions 

 of the Academy, was approved of— Prof. Kluyver made a 

 communication, entitled " Borel's summation-formulae for 

 divergent series." In this paper the author discusses a slight 

 modification of these formulae, which were suggested by Mr. 

 Borel in his " Memoire sur les series divergentes, "(.-/««. de 

 l'£cole norm., t. 16, p. 77, footnote).— Prof. Van der Waals pre- 

 sented a communication, by Mr. J. D. Vander Waals, jun., entitled 

 "The entropy of radiation." The principle of entropy has had 

 to be constantly extended. Originally, entropy was attributed 

 to conditions of equilibrium only. In accordance with the 



