August io, 191 i] 



NATURE 



view to qualify either for the degrees of Master and 

 Bachelor of Technical Science, and 103 for the certificate 

 in technology. A large amount of original work was 

 carried out by members of the staff and the more advanced 

 students pursuing post-graduate courses in the various 

 departments. Much of the work has been embodied in 

 papers read before scientific societies, and published in the 

 scientific and technical Press. The full record affords proof 

 that the school compares favourably in the matter of re- 

 search with other institutions of a similar character. 

 Under the regulations adopted by the committee, a con- 

 siderable number of tests and commercial investigations 

 have been carried out during the year, chiefly in the depart- 

 ments of engineering and chemistry. 



The new handbooks containing the arrangements for 

 the session 191 1— 12 at University College, London, in the 

 faculty of engineering, the school of architecture, and the 

 faculty of medical sciences have now been published. The 

 college is a university centre for preliminary and inter- 

 mediate medical studies. Its faculty of medical sciences 

 comprises the departments of physics, chemistry, botany, 

 and zoology (the preliminary medical sciences), also the 

 departments of anatomy, physiology, and pharmacology 

 (the intermediate medical sciences), and the departments of 

 hygiene and public health and of pathological chemistry 

 (post-graduate study). Each of the departments is also 

 equipped for more advanced work, and provides facilities 

 for research. The faculty of engineering, including the 

 departments of mechanical heating and ventilation, elec- 

 trical, civil and municipal engineering, is intended to pro- 

 vide for students wishing to devote themselves to engineer- 

 ing a systematic training in the application of scientific 

 principles to industrial purposes. The courses are also 

 suited to the requirements of students who intend to enter 

 for appointments in the Indian Public Works Department, 

 engineering department of the General Post Office, depart- 

 ment of the director of engineering and architectural 

 works in the Admiralty, Patent Office, and other similar 

 services. The departments have been recognised by the 

 Board of Trade as providing suitable technical training 

 for marine engineers. Facilities are provided for post- 

 graduate and research work in all the subjects. All com- 

 munications should be addressed to the Provost, University 

 College, London. 



SOCIETIES AND ACADEMIES. 

 Edinburgh. 

 Royal Society, June 19. — Prof. Bower, F.R.S., vice- 

 president, in the chair. — M. Jules Cardot : Les Mousses 

 de 1 'Expedition nationale antarctique ^cossaise. These 

 were collected in various localities visited, and included a 

 number of new species and genera. — Dr. J. Aitken, 

 F.R.S. : Some nuclei of cloudy condensation. Some years 

 previously the author, when enumerating the dust particles 

 in the air at certain regions of the West Highlands remote 

 from centres of population, had noticed from time to time 

 a sudden, and at first inexplicable, increase in the number 

 of dust particles. A recent study of the phenomenon had 

 shown that the increase was due to the sunning of the 

 material on the foreshore of neighbouring islands and 

 coasts. The paper discussed the probable causes of this 

 production of dust particles, and described a number of 

 experiments on the direct effect of sunlight upon various 

 substances. — Dr. A. A. Lawson : Nuclear osmosis as a 

 factor in the mechanism of mitosis. A study of the spore 

 mother-cells of Disporum, Gladiolus, Yucca and Hedera, 

 and the vegetative cells in the root tip of Allium, has re- 

 vealed a series of stages in the development of the mitolic 

 spindle which has hitherto been overlooked. They are 

 important and critical stages concerning the fate of the 

 nuclear membrane, and are to be found in the early pro- 

 phase, preceding the organisation of the equatorial plate. 

 Contrary to the generally accepted view, it has been found 

 that the nuclear membrane does not break down during 

 spindle formation, but behaves as a permeable plasmatic 

 membrane should behave under varying osmotic conditions. 

 The interpretation of these stages throws an entirely new 

 light on the problem of the " mechanism of mitosis," and 



NO. 2l8o, VOL. 87] 



necessitates a revision of the accepted views of nuclear 

 phenomena. It goes to prove that osmotic conditions are 

 active factors in the formation of the acromatic spindle. — 

 Dr. A. G. M'Kcndnck and Dr. Kesava Pai : The rate 

 of multiplication of micro-organisms : a mathematical 

 study. Assuming the law that the rate of increase of fast- 

 growing organisms is proportional to the number of 

 organisms present and to the concentration of the food- 

 stuff, the authors express this in the mathematical form 

 dyjdt = by(a—y). At the beginning, y is small compared 

 with a, so that the constant ab is equal to the rate of change 

 of log y. From the graph which gives log y in terms of 

 time, the value of ab may be readily obtained, and from 

 the indications of the experiments the limit a towards 

 which y tends may be inferred. The quantity also gives 

 by a simple calculation the period of a generation. The 

 numbers calculated from the integrated expression were 

 found to be in good agreement with the numbers obtained 

 by direct measurement. 



July 3. — Dr. Home, F.R.S., vice-president, in the chair. 

 — Prof. A. H. Gibson : The resistance to flow of water 

 through pipes or passages having divergent boundaries. 

 The rate of loss of head in water flowing steadily along 

 various types of expanding tubes was the object of the 

 research — such types as circular pipes with uniformly 

 diverging boundaries, rectangular pipes with two sides 

 parallel and the other pair uniformly diverging, trumpet- 

 shaped pipes with the curved boundary made so that the 

 square of the speed fell off uniformly with distance, &c. 

 In this last-named form there was a distinct reduction in 

 the loss of head in a given length as compared with the 

 loss in uniformly diverging tubes. The divergence which 

 gave greatest efficiency was from 10° to 16 in the rect- 

 angular pipes, and from 7 to 10° in the circular pipes. — 

 Dr. W. T. Gordon : The structure and affinities of Meia- 

 clepsydropsis (Zygopteris) duplex (Williamson). This 

 Carboniferous fern was first recorded by Williamson in 

 1874, when he was investigating the structure of fossil 

 plants from Pettycur, Fife, numerous petioles of the fern 

 being discovered among his specimens. The same species 

 had since been obtained near R£gmy, in France ; but in 

 all these cases only fragments of petioles and pinna? were 

 discovered. Recently, however, stems and roots have been 

 found at Pettycur. In a silicified mass of material several 

 pieces of stems were obtained in close association with 

 innumerable fragments of petioles and pinnce. Certain 

 emergences from the stem were noted, and an examina- 

 tion of the petioles soon established a series showing a 

 continuous variation from the normal petiole trace to a 

 trace which was identical with these emergences. In this 

 way it was proved that the stems and petioles belonged 

 to one and the same species. The stem stele is very 

 simple in structure. The axis consists of a circular 

 cylinder in which the outer zone is composed of long stout 

 tracheides, while the inner zone is formed by a mixture of 

 long narrow tracheides and conjunctive parenchyma. The 

 stem emits petiole and root-traces at long intervals, and 

 occasionally bifurcates dichotomously. In the theory of 

 the medullation of the zygopterid stele, this stem is of 

 some importance, since it exhibits a stage closely similar 

 to that shown in the stem of Ankyropteris corrugata 

 (Williamson). Like some other members of the Zvgo- 

 pteridea:, A. corrugata has a biseriate arrangement of (he 

 primary pinnae, while in M. duplex and others a quadri- 

 seriate distribution of these appendages is shown. In both 

 the quadriseriate and biseriate divisions it is now possible 

 to arrange the stems in a series which demonstrates the 

 gradual medullation of the stems, and is, at the 

 same time, compatible with the geological age of the speci- 

 mens : — 



Quadriseriate divisi. 

 ■;;}(•>-"'>"'■'«*« -••■" (0 No known, 

 1 .') Metaclepsydropsis 

 duplex 

 Upper Car- \ (3) Etapteris diupsilon (2) Aniyrap/ei 



boniferous I [Lygvpterts Grayi) 

 Permian (3) 



a. Aniyropteris] 



scandens I These tnre 



i. Ankvropterisl probabl y, h 

 saruesrecU 

 ti ) 



Decn 



A nkyropt 



Broiignia 



