NATURE 



[May 24, 1900 



Sydney University, New South Wales, has been placed on the 

 list of recognised schools of medicine. 



The Rev. T. Wiltshire has founded a prize to be awarded 

 annually for proficiency in geology and mineralogy. The prize 

 is open to members of the University who have pa.ssed Part i. 

 of the Natural Sciences Tripos, and are not of more than ten 

 terms' standing. 



Prof. J. Ward and Prof. R. Adamson, of Glasgow, are 

 appointed electors to the Gerstenberg studentship in philosophy, 

 open to students of natural science. 



Prof. Leon Guignard has been appointed director of the 

 Paris School of Pharmacy. 



Prof. Ludwig Boltzmann, of Vienna, has accepted the 

 invitation to the chair of physics in the University of Leipzig. 



The Chemist and Druggist announces that Prof. Moissan 

 has been elected a member of the Paris Superior Council of 

 Public Instruction, in succession to the late M, Planchon, 

 deceased. He has also accepted the important post of pro- 

 fessor of chemistry at the Paris Sorbonne, in place of M. Troost, 

 who retires on account of advancing age. 



SCIENTIFIC SERIALS. 



American yournal of Science, May. — Notes on [the geology 

 of the Bermudas, by A. E. Verrill. The present Bermuda 

 Islands are the remnant of a very much larger island, covering 

 an area of about 300 to 400 square miles. A subsidence of at 

 least 80 to 100 feet took place at a comparatively recent period. 

 The Greater Bermuda, as well as the present Bermudas, are 

 composed of shell sand drifted from the sandy flats by the winds 

 in former times into hills, and afterwards consolidated by in- 

 filtration and exposure into what is known as Aeolian limestone. 

 The shell sand is constantly increasing in amount, chiefly by the 

 annual growth and death of small shells, as in former periods, 

 so that the total mass of the islands is probably still increasing 

 beneath the sea. The "red soil" of Bermuda is mainly the 

 ■residue left after the destruction and solution of the limestones. 

 The islands rest on the hidden summit of an ancient volcano. 

 — Some boiling point curves, by C. L. Speyers. The author 

 shows that the equation 



N + n p 



accounts for the boiling point curves of every mixture for which 

 the partial pressures of the constituents are known at some 

 temperature not very far from the boiling point of the mixture 

 under consideration. — Action of ammonium chloride upon natro- 

 lite, scolecite, prehnite and pectolite, by F. W. Clarke and G. 

 Steiger. The authors show how the ammonium chloride re- 

 action can be used for studying the chemical structure of these 

 minerals, and that the orthosilicate formulte for natrolite and 

 scolecite must be discarded. — Siliceous calcites from the Bad 

 Lands, Washington County, South Dakota, by S, L. Penfield 

 and W. E. Ford. The calcites obtained from the new locality 

 have a peculiar crystallisation, being steep hexagonal pyramids 

 instead of rhombohedra. — Studies in the Cyperacese, by T. 

 Holm. This paper deals with the segregates of Carex filifolia, 

 Nutt. — Mineralogical notes, by A. F. Rogers. Describes various 

 peculiar forms of gypsum and calcite. Twinned gypsum crystals 

 from Lebo, Kansas, possess hemimorphic orthorhombic symmetry 

 rather than monoclinic. — The Hayder Creek, Idaho, meteoric 

 iron, by W. E. Hidden. This meteorite, weighing 870 grammes, 

 was found at the bottom of a twelve-foot shaft. No companions 

 have been found. — Explorations of the Albatross in the Pacific, 

 by Alexander Agassiz. This is the author's fourth and last letter 

 to the U.S. Fisheries Commissioner on the cruise of the Alba- 

 tross. It describes the work in the EUice, Gilbert and Marshall 

 Islands, as well as the Carolines and Ladrones. The Truk 

 Archipelago was perhaps the most interesting of the island 

 groups of the Carolines, and it is the only group of the volcanic 

 islands surrounded by an encircling reef which the author has 

 seen in the Pacific, which at first glance lends any support to the 

 theory of the formation of such island groups as Truk by subsi- 

 dence. But a closer examination shows that this group is not an 

 exception to the general rule thus far obtaining in all the island 

 groups of the Pacific visited during this trip, that we must look 

 to submarine erosion and to a multitude of local mechanical 

 causes for our explanation of the formation of atolls and of 



NO. 1595, VOL. 62] 



barrier and encircling reefs, and that, on the contrary, subsidence 

 has played no part in bringing about existing conditions of the 

 atolls of the South and Central Pacific. 



American Journal of Mathematics, vol. xxii. 2. — Remarks 

 concerning the expansions of the hyperelliptic sigma-functions, by 

 Oskar Bolza, are supplementary to two papers, by the same 

 writer, in vol. xxi. pp. 107-125 and pp. 175-190. — On a 

 certain class of groups of transformation in space of three 

 dimensions, by H. F. Blichfeldt, is the carrying on of an investi- 

 gation (by S. Lie) of groups of transformations in 3 variables, 

 defined by the properties : two points have one, and only one, 

 invariant ; s>2 points have no invariants independent of such 

 two-point invariants. This class belongs to a wider class in n 

 variables defined by the properties : not less than m > i points 

 may possess invariants, while s points, s>tn, may have no in- 

 variants independent of the w-point invariants. The wider 

 class includes the group of Euclidean motions in space of 2 or 3 

 dimensions, the group of translations in space of n dimensions, 

 the group of Euclidean motions and similar transformations in 

 space of 3 dimensions, &c. Certain groups are discussed and 

 their general properties stated. — Dr. L. E. Dickson, in a paper 

 on the canonical form of a linear homogeneous substitution in a 

 Galois field, gives a short proof by induction of a result which 

 M. Jordan had previously obtained by a rather lengthy analysis. — 

 Dr. E. O. Lovett writes on families of transformations of straight 

 lines into spheres. If a plane tr containing two points E and E-^ 

 moves upon a coincident plane ff^ containing two straight lines 

 ^and^i, so that E remains upon g and E^^ upon g■^, the two 

 planes form a mechanism possessing the following well-known 

 properties : Every point of a traces an ellipse upon <rj, and 

 every point of o-j traces a lima9on upon o- {cf. Chasles, Apercju, 

 p. 49), a circle c of radius a in <r rolls upon the inner side of a 

 circle c^ of radius 2a in (Tj. Every point of <r describes a straight 

 line passing through the centre of c^. Any two of these lines, 

 with the points which generate them, can be taken for g, g^ and 

 E, E^ in defining the movement. Mr. E. M. Blake's object, 

 in his article on the Ellipsograph of Proclus, is to study (i) the 

 curves generated by the points of a and o-j ; (2) the ruled surfaces 

 generated by any straight line carried by <r or a^ and not 

 parallel to them ; (3) the curves enveloped by any straight line 

 of rr or tr^ ; (4) the developables enveloped by carried planes (cf. 

 Cay ley, on the kinematics of a plane, Q.J. xvi. 1878 ; Schell, 

 "Theorie der Bewegung und Krafte," i. pp. 227-230, and 

 articles by IJurmester). — Mr. N. J. Hatzidakis, in displacements 

 depending on one, two, . . . k parameters in a space of n di- 

 mensions, extends to the general case results obtained for 4 

 dimensions by Prof. Craig (vol xx. 2) and M. Darboux. — The 

 main object of Dr. G. A. Miller on the product of two substi- 

 tutions is to prove the following theorem : — If/, m, n are any 

 three integers greater than unity, of which we call the greatest 

 /•, it is always possible to find three substitutions {L, M, N) of 

 k-\-2ox some smaller number of elements, and of orders /, m, n 

 respectively, such that LM=-N. 



Annalen der Physik, No. 4. — Temperature and potential 

 gradient in rarefied gases, by G. C. Schmidt. When a yacuum 

 tube is heated, the positive light becomes stratified. The 

 stratifications increase in breadth as the temperature increases. 

 Eventually, the positive light retires towards the anode, so that 

 the discharge becomes dark. At the kathode, on the other 

 hand, an increase of the temperature produces an extension of 

 the glow light, such as is produced by an increase of the current 

 strength. When the dark discharge has set in, the potential 

 gradient is greatest at the anode, and is proportional to the 

 distance from the kathode. — Mechanical motions under the 

 influence of kathode rays and Rontgen rays, by L. Graetz. 

 Rotations similar to those produced by Quincke in liquids may 

 be produced in air ionised by X-rays, by mounting light di- 

 electric bodies provided with agate caps on needle points in 

 the space between two condenser plates exposed to the rays. 

 The sense of the rotation depends upon the initial tendency, 

 except when the rotating body contains a metallic substance, in 

 which case the direction of rotation depends upon the direction 

 of the rays and the electric field. The rotations are explained 

 by the electrostatic forces between the wall of the tube and the 

 parts of the body charged by the ions. The author beUeves 

 that these rotations furnish an explanation for the rotations 

 under the influence of kathode rays first observed by Crookes. — 

 Atomic and molecular magnetism, by S. Meyer. Special in- 

 vestigations of the magnetic susceptibilities of copper compounds 

 have shown that there is no essential difference between cupric 



