Feb. 7, 1884] 



NA TURE 



549 



London. — At King's College, Prof. W. Grylls Adams, 

 F. R.S., will continue the course of lectures on Light, and the 

 Scientific Principles involved in Electric Lighting, during the 

 remainder of the session. A course of practical work in Electrical 

 Testing and Measurement with especial reference to Electrical 

 Engineering will also be carried on under his direction in the 

 Wheatstone Laboratory. The lectures will be given once a 

 week — on Mondays, at 2 p.m. — and the Laboratory will be open 

 on Wednesday and Friday from i to 4. 



SCIENTIFIC SERIALS 



The monthly parts of the Journal of Botany for 1S83 con- 

 tain many useful and interesting papers. Among the more 

 important must be rea;arded Mr. J. G. Baker's synopsis of the 

 genus Selagitiella. This is not yet completed, but already ex- 

 tends to nearly 100 species, many of them now described for the 

 first time. This is understood tj be an insialment of a complete 

 monograph by Mr. baker of the Vascular Cryptogams, excluding 

 ferns, a work eagerly demanded by botanists. — The additions 

 to the phanerogamic flora of Great Britain are not yet com- 

 pleted ; and the palm of recent discoveries must be awarded to 

 Mr. Arthur Bennett. In this year's record he describes and 

 figures two, one of them, Potamogeloti Griffithii, new to science, 

 from a lake in Carnarvonshire. The other, Naias marina, is a 

 native of the "Broads" of Norfolk. This is rendered more 

 interesting by the discovery, by other botanists, of another spe- 

 cies of Naias, N. alngmnsis, also during the present year, in 

 Lanca-hire. It is not many years since the genus was first 

 found in Britain ; and the only species hitherto known, N. 

 flexilis, has been gathered only in Scotland and Ireland. — The 

 structure and distribution of the Characea; are still engaging 

 attention from Mes-rs. H. and J. Groves and others; and of 

 this cryptogamic order, another species, Chara Braiinii, has also 

 been added to the flora of Great Britain. — Mr. H. Boswell also 

 describes two new British mosses, Bryum gt-mmiparuin, from 

 Breconshire, and Sphagntim torreyanum, from Shropshire. — 

 Messrs. R. M. Christy and H. Corder contribute an interesting 

 paper on the cross-fertilisation of Arum maculatum. — Numer- 

 ous other articles and short notices of more local and special 

 interest fill up the number. 



The second part of vol. xiv. of PringshcinC s yalnblicher fiir 

 vuscmchajtliche Botanik contains two important articles on 

 cryptogamic botany : — Dr. A. Fischer, on the occurrence of 

 crystals of gypsum in the Desmidiea; show s that they are of very 

 wide distribution in the family, as well as in other freshwater 

 algoe such as Spirogyra, though by no means universally present. 

 He believes it to be simply a product of excretion in the process 

 of metastasis, whether present in the form of crystals or dis- 

 solved in the cell-sap. Dr. O. Miiller, on the law of cell divi- 

 sion in Meloiira arenaria, offers an important contribution to 

 the life-history of the diatoms. By a most careful series of 

 observations he establishes the law that "the larger daughter- 

 cell of the «th generation divides in the following or (« -h l)st 

 generation, while the smaller daughter cell always divides only 

 in the (« + 2)nd generation," by an argument which is too 

 long to go into here. He deduces from this law the reason of 

 the comparatively rare occurrence of the auxospores, by which 

 the original size of the species is restored after the continued 

 degradation which it necessarily undergoes in the ])rocess of 

 division. — B. Fritsch contributes aho a paper on coloured 

 granular constituents of the cell-contents. 



The second part of vol. iv. of En^^ler's Botanische Jahr- 

 biicher for 1883 contains a continuation of its very valuable 

 review of the more important works on systematic and geo- 

 graphical botany which appeared in 1882. — The other papers 

 are : — By T. Wenzig, on the genus Fraxinns. — By F, Moewes, 

 on hybrids of Mentha arvensis and M. aqualica. — By E. 

 WarDiing, on the order Podostemacea;. 



Archives of the Physical and Natural Sciences, Genct'a, Decem- 

 ber 15, 1883. — Meteorological resume of the year 1882 for 

 Geneva and the Great Saint- Bernard, by M. A. Kammermann, 

 Assistant-Astronomer. — On the ancient lake of the Soleure dis- 

 trict (coloured map), by M. Alph. Favre. The existence of this 

 • lacustrine basin confirms the conclusion arrived at by other 

 geological studies, that during the early postGlacial epoch a far 

 gre-ter portion of Switzerland was under water ihan at present. 



— Descriptive notice of the meteorological observatory installed 

 on September i, 1S82, at Senilis, canton of Appenzell, 2467 

 metres above sea-level. — On the periodical oscillations of the 

 ground, determined by the spirit-level (fifth year, 18S2-S3), by 

 M. P. L. Plantamour. — On the theory of dynamo-electric ma- 

 chines, by M, R. Clausius. These machines having in their 

 practical development outstripped the theory of their construc- 

 tion, an attempt is made in this elaborate paper to expound a 

 theory more in harmony with the results already obtained than 

 are any of the mathematical formulas hitherto employed to 

 represent them. 



Rendiconto of the Sessions of the Accademia delle Scienze di 

 Bologna for the year 1S82-83. Nov. 19, 1882. — Memoir on the 

 " null envelopes" of the second class in a given sy>tem of points 

 affected by given coefficients, showing how, from the general 

 formula, others may be deduced, rendering more evident the 

 property of the envelopes, and solving some questions connected 

 with the momenta of the second order of said system, by Prof. 

 Ferdinando P. Rufifiani. — On three sicephalous monsters, and 

 more particularly on the seven-month Janus recently born in 

 Bologna, by Prof. Luigi Calori. — Note on the extremities of the 

 motor nerve fibres in the striated muscles of the torpedo ( Tor^ 

 pedo marmorata) treated with bichloride of gold and cadmium, 

 by Prof. G. V. Ciaccio. — Microscopic researches on the traces 

 of electric sparks incised on glass, by Prof. Elmilio Villari. — 

 On the electric figures of condensers, by the same author. 



November 26. — A systematic classification of the genus Puc- 

 cinia, by Prof. Cocconi and Dr. F. Morini. — On a case of 

 hypertrophic hepatitis, by Prof. C. Taruffi. — Symptomatic and 

 anthropometric studies on the cretinism prevalent in the Valle 

 d'Aosta, Piedmont, by the same author. — Some new researches 

 on the artificial reproduction of the spleen, by Prof. Guido 

 Tizzoni. — On the results of the measui'es hitherto adopted to 

 improve the soil and climate of malarious districts in Italy, by 

 Dr. Paolo Predieri. — A new contribution to the study of Addi- 

 son's disease, by Prof. Ferdinando Verardini. 



January 14, 1883. — On a fossil cetacean (Orca cetoniensis) 

 recently discovered at Cetonain Tuscany, by Prof. G. Capellini. 

 — A study of some reactions of phosphuretted hydrogen gas, by 

 Dr. Alfredo Cavazzi. 



January 28. — On a rapid method for determining the lunar 

 motions, by Prof. A. Saporetti. — New researches on the ana- 

 tomy and pathology of the placenta in mammals, by Prof. G. 

 Escolani. 



February 11. — Notes on the history of geodesy in Italy from 

 the earliest times down to the second half of the present century, 

 by Prof. P. Riccardi. — Experimental researches on the hyper- 

 trophy and partial regeneration of the liver, by Dr. V. Colucci. 

 — On the relative length of the neck in both sexes, and on the 

 best method of making these anthropometric mea-ureraents, by 

 Dr. G. Peli. — On the preventive inoculation of contagious 

 pleuro-pneumonia for cattle by means of intravenous injection 

 of the virus, by Prof. A. Golti. — Anatomical researches on five 

 bovine monstrosities, by Prof. G. P. Plana. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, January 10. — "Experimental Researches on 

 the Electric Discharge with the Chloride of Silver Battery." By 

 Warren De La Rue, M.A., D.C.L., Ph.D., F.R.S., and Hugo 

 MuUer, Ph.D., F.R.S. 



Plasticity and Viscosity of Strata. — During our experimenis we 

 have often been struck by the evident plasticity of strata w hose 

 form at times becomes modified when they meet with an ol stacle 

 or are influenced liy other causes, as, for example, the cri ssing 

 of other strata produced by a separate discharge. 



One of our tubes, No. 9, with a residual hydrogen vacuum, 

 has a diaphragm in the centre \ of an inch, 0-63 cm. , thick, through 

 the centre of which there is a hole \ of an inch, o'63 cm., in 

 diameter. To the end of the tube is attached a potash absorp- 

 tion chamber, the heating and cooling of which causes a change 

 in the number of strata ; when the number of strata increases 

 they approach closer and closer to the diaphragm, and occasion- 

 ally one threads itself through it, as if squeezed through, and its 

 form is gradually changed thereby. 



A tube. No. 368, Fig. i, with a hydrogen residue gives evi- 

 dence of the viscosity of a stratum. 



