39& 



NATURE 



[May js. 



-35* C RadloiiKtrr, in concentrated U-am of electric 

 arc, .slopped by ch;ircoal liijuid-air vacuum, and started 

 iij^iiin bv nu-rcury vapour at a pressure o( about one fifty- 

 milliv)nth of an atmosphere. Activity again arrcvted on 

 Ircpzing out the mercury vapour in liquid air, hit. 

 Fratuis Fox. — (1) Radium brumidt- from pitchblende found 

 in Jrenwith .Mine, St. Ives Consolidated Mines, St. Ives, 

 Cornwall. {2) S|H*cimen of rich pitchblende on- from the 

 mine. .Mr. C. 'J'. A'. Wilson. F.K.S. — Exhibition of the 

 tracks of ionising particles in gases. (1) Tracks of a 

 particles from r.idmm through air. (2) Tracks of ionising 

 particles produced by X-rays in air. The trail of ions left 

 by each ionising particle is made visible by condensing 

 water upon the ions. The Mational Physical Laboratory. — 

 lonisation in the electric furnace (exhibfted by Dr. J. A. 

 Marker, K.R.S.. and .Mr. C. G. Eden;. Prof. J. Sorman 

 Collie, F.K.S. — Tubes showing electric discharge through 

 neon. (1) 'lubes showing the electric discharge through 

 neon at high pressures. (2) Table showing the canal rays 

 in neon. :»/r. C. W. Rajfety. — Enlarged photographs of 

 the forms assumed by the brush discharge in air at re- 

 tluced pressures. Proj. A*. Wilson and Mr. W. H. Wilson. 

 — (i) .An improved high-tension discharge apparatus. (2) A 

 high-tension electrostatic wattmeter (Prof. E. Wilson). 

 Prof. J. A. Fleming, F.R.S. — Experiments showing visibly 

 the oscillatory discharge of a condenser by Hemsalech's 

 method, and its magnetising action on finely divided iron 

 cores. Mr. S. G. Brown. — (1) Telephone relays. 

 (2) -Model of electrical stethoscope. 



I'rof. .4. Liversidge, F.R.S.—{i) Series of sections of 

 gi>ld nuggets and photographs to illustrate the same. 

 (2) Specimens and sections of Australian meteorites, and 

 photc^raphs. Prof. W. J. Pope, F.R.S. — Photomicro- 

 graphy in natural colours. Photomicrographs of rock 

 sections, chemical preparations, and crystal interference 

 figures are exhibited. The photographs were taken between 

 crossed Nicol prisms by the Dufay process, in which the 

 colours of the objects arc reproduced. Prof. E. G. Cokcr. 

 — Interference colours produced by transparent materials 

 under stress. A beam of plane or circularly polarised light 

 is passed through a plate of xylonite cut Into any selected 

 shape and loaded in any convenient manner. The material 

 when stressed behaves like a doubly refracting crystal, and 

 Ihe two rays, into which the incident beam is divided, \>ro- 

 <hue interference colours when passed through a Nicol's 

 prism. The stress distribution may be inferred from the 

 colour fringes produced. Prof. J. Eustice. — Experiments 

 on stream-line motion in curved pipes. By means of fila- 

 ments of coloured water, it is shown that when water is 

 flowing from a straight to a curved pipe some of the fila- 

 ments approach the sides of the pipe and cross from the 

 outside to the inside of the curve, close to the walls. 

 Several colours are used in the glass pipes, and the inter- 

 lacing of the filaments caused by the vortex motion is 

 clearly exhibited. .Mr. C. E. Larard. — Twisted, cylindrical, 

 and castellated metal specimens. .Mr. J. E. Marsh, F.R.S. 

 — (i) Experiments showing the separation of a homo- 

 geneous solution into three layers when the solution is 

 w.armed. (2) Solutions of certain - r not 



miscible with excess of ether. 



Prof. ir. M. Thornton. — The electric i iuiri.;' s a>siiciated 

 with vegetable cells. When an electric current is passed 

 through a weak emulsion, in water, of typical animal and 

 vegetable cells, such as blood corpuscles, yeast, bacteria, 

 cind unicellular algae, the animal cells appear to be driven 

 to the positive pole, the vegetable cells to the negative, 

 provided that the latter are from fresh, active growths. 

 The movement reverses with the direction of the current, 

 and is dead beat. The Director, Royal Botanic Gardens. 

 Kew. — Cushion plants and their seedlings. The exhibit 

 includes specimens and photographs of the balsam bog of 

 the Falkland Islands (.isorella glebaria, .\. Gr.ny, Umbelli- 

 fcrac), with a series of living seedlings raised in the Royal 

 Botanic Gardens, Kew. The John Innes Horticultural 

 institution. — (i) " Chim.Tras " and Winkler's graft- 

 hybrids, from Prof. K. Baur (BerlinV (2) .\ case of 

 coupling in Pisum. between roundness of seed and power 

 to produce tendrils, in the ratio 03 : 1 : i : 63. Mr. .4. D. 

 HnH. F.R.S. — .\ biological factor in soils limiting the 

 activity of bacteria in producing plant food. Bacteria play 

 an important part in the production of plant food in the 

 soil from the accumulated organic rr-''' - •< '■• n 



NO. 2168, VOL. 86] 



other thingA ..f '^*; ferlility of the mj,. .> ^.., 



connect<-d with : t of bacterial activity. It i 



been shown, hou' ° a factor exists in ordmurv ^< 



limiting the activil) ut bacteria; thi» factor ii> b>> 

 .'md appears to consist of large devtructive or^^ 

 When smU are kept in moist, warm condition* .. 

 supplied with organic maiter, a* in a fint-nhouse, 

 a marked accumulation of tli<- lim;'-"' '■■".r; a ,,,,... 

 accumulation occurs in the •»oiU of - !n». On 1 



other hand, dry soil conditions ai lable i<> 



factor. Heating the »oil to 55" C, prolonged dr 

 lower temperatures, or treatment with variou!» an 

 such as toluene, kilU the factor and lead* to a 

 increase of bacterial aitiviiy. In field and greenhtj- 

 there is a large produi i-m of plant ftKxl, and in 

 farm soils an incr'-.i-il r.ite <>( decompt)sition. 



Prof. n. E. Armstrong. F.R.S.. and Dr. E. I 

 strong. — The actk>n of stimulants thormones) in pi- 

 enzymic activity. The sj>erimens shown arc in illu- 

 of results described in recent communications on the Jui. 

 tions of hormones in stimulating enzymic change in r»i.; 

 tion to narcosis and th',- phenomena of degener. 

 generative change in liviii;^ structures, and on 

 of hormones in regulating metabolism. Liki 

 grain, leaves are shown to be provided with p 

 differential septa through which strong acids, salt- 

 ally, and substances such as the sugars do not p 

 which are freely permeable by organic vapours, we;i'. 

 ammonia, and a few salts (mercuric chloride, &c. ). s 

 passage of the excitant into the leaf is shown in the c. - 

 of the common laurel {Prunus laurocerasus) by the lib* :• 

 tion of liydrogen cyanide, and in the case of the spot;- ' 

 Japanese laurel (.Aucuba japonica) by blackening ilu- 

 the decomposition of the glucoside aucubin. Th' 

 substances are for the most part non-electrolyte- 

 have little, if any, chemical activity. Prof. R. T. 

 and .Mr. J. E. Barnard. — (i) The bactericidical ;: 

 light produced by a quartz mercur}' vapour lamp. 

 ments on the bactericidical action of light indicate 

 quartz mercury vapour lamp, in relation to its curr- . 

 sumption, is the most economical source at present av;i 

 able. The most actively bactericidical region in the rar! > 

 arc spectrum is that portion of the ultra-violet 

 A 3280 and 2260. These radiations are produced !; 

 the mercury arc, and the action extends still further, pr.i. - 

 tically to the limit of transmission by quartz. Owing to 

 the almost entire absence of lieat radiations in the mercury 

 arc, any arrangement for heat absorption becomes un- 

 necessary. This is an advantage of considerable mom^-nt, 

 as any such method at present in use substantially increases 

 the necessary exposure. (2) Apparatus for disintegrating 

 bacterial and other organic cells. The apparatus consists 

 of a metal containing vessel, in which a number of steel 

 balls are placed, and which is caused to rotal- ' '^■ 



balls are kept in position at the periphery of the \ 

 a central steel cone, which, by suitable means, 

 vented from rotating. Grinding action takes place binwetrn 

 the steel balls and the inner surface of the vess»-l. The 

 efficiency of the method is high, as after subjecting bact-ria 

 to the grinding process for from fifteen to twenty minulps, 

 very few, if any. whole cells remain. Even tho*;e that are 

 apparently whole have evidently parted with their c»ll 

 contents, as may be demonstrated by the difficulty <>t -:.i'n- 

 ing them by any recognised bacteriological meth« 

 Henry Crookes. — Photographs and living cultun- 

 phosphorescens, showing the germicidal action ot M>;nt 

 metals. Nutrient gelatin-agar is poured into Petri dishes 

 containing small pieces of metal ; when the medium h.is 

 set, the surface is infected with B. phosphorescens. After 

 twenty-four hours the bacteria grow luxuriantly, except in 

 a zone surrounding the piece of metal, which remains 

 entirely sterile. The extent of this death-zone varies with 

 different metals. Prof. M. C. Potter. — Electrical effects 

 accompanying the fermentative activity of yeast. Th^ 

 apparatus shown consists of a glass jar containing a 

 porous cylinder, and into each of these are introduced solu- 

 tions of glucose of equal concentration. Two r' i-'-iin, 

 electrodes are placed one in the jar and one in th' 

 cylinder, and on the introduction of yeast into ori' 

 solutions, the whole constitutes a tvpe of galvanic c<il. 

 Mr. S. G. Shattork and Mr. L. S. Dudgeon. -d^ R«.«5sf 

 ance of Bacillus pyocyanctis to dryinij in vn' 



