45 



jVA TURE 



[November 9, 1893 



As the result of a memorial addressed to them by the 

 demonstrators in the various departments of Natural Science, the 

 Hebdomedal Council have appointed a committee, consisting of 

 Mr. T. Raleigh, of All Souls, and Mr, T. H. Grose, of Queen's 

 College, to inquire into the position and status of the demon- 

 strators at the museum. 



Cambridge, — Dr. Forsyth has been appointed chairman of 

 the Examiners for the Mathematical Tripos, Part II., and Mr. 

 Welsh, of Jesus College, for Part I. 



Pro.f. Ramsay, of University College, London, has been 

 elected Examiner in Chemistry for the Natural Sciences Tripos. 



At St. John's College, Mr. E. W. Macbride, Hutchinson 

 Research Student, and University Demonstrator in Animal 

 Morphology, has been elected to a Fellowship. Mr. MacBride 

 took a Mi:.t class in both parts of the Natural Sciences Tripos 

 (zoology and botany) in 1890-91, and is the author of various 

 morphological papers based on researches conducted in Cam- 

 bridge and at the Zoological Station at Naples. He has been 

 President of the Union Society, and is well known as a vigorous 

 debater. At the competition for Fellowships on this occasion 

 there were no less than seven candidates in Natural Science, 

 v^ho had all taken first class honours in the Tripos as students 

 of St. John's. 



SCIENTIFIC SERIALS. 



Wiedemann's Annalen dcr Fhysik'icnd Chemie, No. 10. — On 

 air vibrations, by A. Raps. The changes of density at the nodes 

 of open and closed organ pipes were recorded by allowing a 

 beam of strong white light to fall upon the mirror of a Jamin 

 interference refractor. One of the reflected beams was sent 

 through a pipe at the node, the other through a box containing 

 undisturbed air. After reunion by the second mirror, these two 

 beams gave rise to interference fringes, which were displaced 

 during the changes of density accompanying the sound of the 

 pipe. A section across these fringes, consisting of bright and 

 dark points, was received upon a revolving drum carrying sensi- 

 tive paper, and the oscillation of the points gave rise to a series 

 of curves representing the sound vibrations with very fair accu- 

 racy. A series of eighty-eight photographs are reproduced, 

 which give valuable hints concerning the structure of the various 

 notes, and also some vowels and consonants produced in the 

 open air.— Luminous phenomena in electrode-less vacuum tubes 

 under the influence of rapidly alternating electric fields, by H. 

 Ebert and E. Wiedemann. This paper, a sequel to the general 

 investigation published in No, 9, deals with the details of the 

 phenomena observed between the condenser plates of a Lecher 

 wire system in the case of spheres, cylinders of various lengths, 

 conaxial double cylinders, and glass parallelepipeds with plane 

 ends. — Heat of dissociation in electro-chemical theory, by H. 

 Ebert. Calculations based upon heat of dissociation and electro- 

 lytic work show that the forces of chemical affinity are chiefly of 

 an electric nature, that the forces due to "valency- charges" are 

 the most powerful of any atomic forces, and that any additional 

 chemical forces are, in comparison, infinitesimal. — Equipotential 

 lines and magnetic lines of force, by E. von Lommel. Some 

 further photographic tracings of these lines are given, and their 

 bearing upon the Hall effect is discussed. — Objective representa- 

 tion of interference phenomena in spectrum colours, by the same 

 author. Simple arrangements are described for exhibiting 

 Newton's rings, gypsum fringes, convergent polarised light 

 phenomena, and fringes produced by the rotation of the plane 

 of polarisation in quartz prisms, upon a screen. For Newton's 

 rings the light from the heliostat is reflected by a colour plate, 

 and falls upon a lens which produces an image of the sun at its 

 focus. By placing a slit at this focus and a prism between slit 

 and lens, the rings in all the spectrum colours may be thrown 

 upon the screen by shifting the slit. — Papers by Kayser and 

 Runge, P, Czermak, and R. J. Holland have already been 

 mentioned. 



The pages of the Botanical Gazette for September contain 

 but little except reports of the proceedings of the Botanical 

 Section of the Madison meeting of the American Association 

 for the Advancement of Science, of the Madison meeting of the 

 Botanical Club, and of the Madison Botanical Congress, That 

 for October contains several important papers : — On the fructi- 

 fication of Junipcnts, by Mr. J. C. Jack, who states that in 

 America the fruit of the English species of juniper does not 



NO. 1254, VOL. 49] 



mature until the autumn of the third year after blossoming p 

 on the development of the embryo-sac of Acer 7-ndnitn, by Mr, 

 D, E, Mottier ; on the achenial hairs of Composilce, by Miss 1 

 M. A, Nichols ; and on the bacterial flora of the Atlantic Ocean 

 in the vicinity of Woods Holl, Mass., by Mr. H. L. Russell. 

 The results obtained by the author accord in a general way with 

 those previously made in the Mediterranean. While the water 

 and underlying sea-flow are filled with bacterial life, they are by 

 no means in an entirely quiescent condition. Both water and 

 mud are peopled with micro-organisms which are undergoing 

 their cycle of development here as elsewhere. 



The Nos. of \heJoiirnalo/ Botany for October and November 

 are almost entirely occupied by papers on local and descriptive 

 botany, including the completion of Mr. E. G. Baker's synopsis 

 of Geneva and species of Malvece, and a sketch of the botany 

 of Ireland, by Mr. A. G, More. 



The summer number of the yaJu-biich (Austrian Geological 

 Survey) contains contributions by Drs. Emil Tietze, von Wohr- 

 mann, Bittner, Skuphos, and others. Dr. Emil Tietze writes on 

 the " Geology of the Ostrau District." Great hopes were raised 

 in this neighbourhood by the discovery of coal near Wagstadt, 

 in the Upper Oder valley, but Dr. Tietze informs us that the 

 coal occurs only locally and in mere fragments. With regard 

 to the age of the Ostrau beds, he argues that they should be 

 grouped with the upper and not with the loiver carboniferous 

 series. They rest unconformably on the Culm grits and shales 

 and are conformably succeeded by the Schatzlar beds, a deposit 

 closely resembling the Ostrau beds in general character. 

 Another paper by Dr. Tietze aiscusses the prospects of the salt 1 



industry in East Galicia. — Baron v. Wohrmann contributes an 

 article on the " Systematic Position of the Trigonida; and the 

 Descent of the Nayadidre." He shows that both the Trigonidje 

 and the Nayadidae have true heterodont hinges, and that there- 

 fore the classification into schizodont and heterodont bivalves 

 suggested by Neumayr cannot be carried out. Taking the 

 fresh-water bivalve Unio as type-form of the Nayadidse, 

 v. Wohrmann traces the phylogenetic relationship of this family 

 with the genus Trigonodus (Up. Triassic shore deposits), and 

 through Trigonodus with the ancient ancestral type, Myophoria> 

 (Devonian to Rha;tic). — Dr. Theodor Skuphos completes his 

 survey of the Partnach beds in the Northern x\lps. He found 

 in the Vorarlberg deposits of this age a new fossil Saurian, 

 which he names Partanosattrus Zitteli. Dr. Skuphos thinks it 

 probable that this Saurian is identical with certain remains 

 found in extra-alpine deposits of Upper Muschelkalk age in 

 Wiirtemberg. 



SOCIETIES AND ACADEMIES. 



London. 



Physical Society, October 27. — Prof, J. Perry, F.R.S., 

 vice-president, in the chair. — Mr. E. C. Rimmgton read a paper 

 " On the Behaviour of an Air-Core Transformer when the 

 Frequency is Below a certain Critical Value." Taking the ordi - 

 nary differential equations for two circuits having self and 

 mutual induction, and assuming sinusoidal E.M.F.'s and con- 

 stant coefficients, the author shows that although the difference 

 of phase between the primary P.D. and primary current is- 

 always diminished on closing the secondary circuit, yet under 

 certain circumstances this closing increases the impedance of 

 the primary. With constant P.D. this means that closing the 

 secondary decreases the primary current, a phenomenon not 

 usually observed. The critical conditions necessary for in- 

 creased impedance are fully worked out in the paper, as well 

 as those under which this increase becomes a maximum. In the 

 case of two identical coils with no magnetic leakage, the critical 



value of o (a =- where/ — 2ir times the frequency, L the 



inductance of the primary, and r^ its resistance) is ^/2, whilst 



that to give maximum impedance is . The maximum in- 



crease possible is 15^ per cent. The corresponding values are 

 given for various amounts of magnetic leakage in tabular form, 

 and curves were exhibited at the meeting showing how the im- 

 pedance, current, power, and magnetising effect vary for different 

 values of a. To test his conclusions the author made experi- 

 ments on two coils close together, the observed increase in im- 

 pedance amounting to 3 '2 per cent. In addition to the analytical 



