January 29, 1903] 



NA TURE 



309 



charge followed the same rule. We believe that the motive 

 power for the descent was gravity, as in the case of any ordinary 

 avalanche. 



The accepted mechanism of a volcanic eruption is that a 

 molten magma rises in the volcano chimney. It consists of 

 fusible silicates and other more or less refractory minerals, some- 

 times already partly crystallised, and the whole highly charged 

 with water and gases, which are kept in a liquid state by the 

 immense pressure to which they are subjected. When the mass 

 rises nearer the surface and the pressure is diminished, the water 

 and gases expand into vapour and blow a certain portion of the 

 heavier and less fusible materials to powder, or, short of this, 

 form pumice stone, which is really solidified froth, and they are 

 violently discharged from the crater. When the greater part of 

 the steam and gases hvve been discharged, the lava, still rising, 

 gets vent either over the lip of the crater or often through 

 a lateral fissure, and flows quietly down the side of the 

 mountain. 



It is quite recognised that these phenomena may occur in 

 various relative proportions. We believe that in these Pelean 

 eruptions, the lava which rises in the chimney is charged with 

 steam and gases, which explode as usual, but some of the 

 explosions happen to have only just sufficient force to blow the 

 mass to atoms and lift the greater part of it over the lip of the 

 crater without distributing the whole widely in the air. The 

 mixture of solid particles and incandescent gas behaves like a 

 heavy liquid, and before the solid particles have time to subside, 

 the whole rolls down the side of the mountain under the influence 

 of gravity, and consequently gathers speed and momentum as it 

 goes. The heavy solid particles are gradually deposited, and the 

 remaining steam and gases, thus relieved of their burden, are 

 free to ascend. 



The effect of avalanches in compressing the air before them 

 and setting up a powerful blast, the effects of which extend 

 beyond the area covered by the fallen material, has long been 

 recognised. A group of large trees was overthrown by the 

 blast of the great avalanche from the Attels on the Gemmi 

 pass in 1S95 ; all lay prostrate in directions radiating away 

 from the place where the avalanche came down. 



THE ZOOLOGICAL SOCIETY'S MEETING. 

 ""THE monthly meeting of the Zoological Society of London, 

 ■*• at their house in Hanover Square, held on January 22, 

 was well attended, it being expected that some account of the 

 operations of the committee of reorganisation recently appointed 

 by the council, on the occasion of the change in the secretary- 

 ship, would be given. The chair was taken by His Grace the 

 Duke of Bedford, K.G., the president, at 4 p.m., and the rfew 

 secretary, Mr. W. L. Sclater (lately director of the South 

 African Museum, Cape Town), was present for the first time. 

 After the election of new fellows and other routine business, 

 the report of the council was read by the secretary. It stated 

 that thirty additions had been made to the Society's menagerie 

 during the month of December last, amongst which was a very 

 fine pair of the one-wattled cassowary (Casuariits uniappendi- 

 culatus), deposited by the Hon. Walter Rothschild, M. P. 

 The report also stated that the total income of the Society in 

 1902 had been 29,077/., being, in spite of the bad weather that 

 had prevailed during the summer, only 273/. less than the 

 receipts of the previous year, and being the sixth largest 

 annual income ever received by the Society. The report of 

 the reorganisation committee was then read to the meeting by 

 Sir Harry Johnston, K.C.B., the hon. secretary of the com- 

 mittee. It was divided into numerous heads relating to every 

 branch of the Society's affairs, and containing recommendations 

 thereon. Many of these were of a technical character, but 

 important changes were advised under the heads of the gardens 

 and menagerie, the prosectorium, the staff at Hanover Square 

 and the secretaryship. The charge of the Society's gardens 

 and menagerie was proposed to be entrusted to a member of 

 the council, Mr. W. E. de Winton. Mr. de Winton would 

 thus, for the present, take the place of Mr. Clarence Bartlett, 

 who has retired on account of bad health on a pension. 

 This appointment being for a year only would give 

 time for the selection of a new superintendent, who must 

 possess special qualifications such as were not easily to be 

 found. Various buildings, such as the giraffe house, the small 

 mammals' house and the bears' dens, were pointed out as 

 specially requiring reconstruction, and there should be a new 



NO. 1735, VOL. 67] 



seals' pond and better accommodation for the polar bears. 

 Alterations were also recommended at the monkey and antelope 

 houses and in other buildings. A foreman keeper should be 

 appointed to make periodical tours of inspection in the gardens 

 during the day, and the keepers should be forbidden to accept 

 gratuities, to trade in living animals or to keep them without 

 the sanction of the authorities. The prosectorium should be 

 carried on by the present officer in charge (Mr. F. E. Beddard, 

 F.R.S.), but on lines to be laid down by a scientific committee, 

 so that the work should have a more definite object. The 

 prosector should also have a veterinary assistant, who would 

 help in the postmortems and look after the health of the animals 

 in the menagerie. The salary of the new secretary would begin 

 at 600/. a year, and his work would be under the supervision 

 of various committees, of all of which the president would be 

 an ex officio member. These committees were to be directly 

 responsible to the council. The garden-guide, which the 

 council had formerly granted to the secretary as part of his 

 emolument, had now reverted to the Society, and would be 

 improved and carried on for their benefit. 



After the report had been read, the recommendations based 

 upon it and adopted by the council were read from the chair by 

 the president, and it was agreed that they should be printed 

 and sent to the fellows. Notice of a motion was then given by 

 Mr. A. G. Ross that copies of the testimonials tendered to the 

 council by Mr. W. L. Sclater, the newly elected secretary, and 

 by Dr. Chalmers Mitchell (one of the unsuccessful candidates) 

 should be printed and sent to all the fellows. This motion was 

 ordered to be discussed at the next general meeting on February 

 19- ■ 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



AT Bedford College on Thursday, February 5, a lecture on 

 " Electricity and Matter " will be given by Sir Oliver Lodge. 



The first two scholarships at Oxford granted under the terms 

 of Mr. Rhodes's will have just been awarded by the Government 

 of Rhodesia to two students of the Jesuit College in Bulawayo. 



The award of valuable scholarships by private institutions 

 deserves encouragement. We are glad, therefore, to notice that 

 as a result of the recent scholarship examinations, the board 

 of control of the Electrical Standardising, Testing and Training 

 Institution has made the following awards :— To W. H. C. 

 Prideaux, of Shrewsbury School, a Faraday scholarship, value 

 eighty guineas, tenable for two years ; to N. S. Smith, of 

 Wellingborough School, an exhibition, value thirty guineas, 

 tenable for two years ; to W. d'Arcy Madden, of Haileybury 

 College, and to Frederick Smith, of Aldenham College, special 

 prizes of ten guineas each. 



It is understood that the Carnegie Trust will shortly take 

 active steps to encourage post-graduate research. The present 

 idea is that with the assistance of the Trust, students, after 

 graduating, will be enabled to prosecute thoroughly their par- 

 ticular branches of study. Mr. Carnegie is reported not to 

 consider suitable the post-graduate organisation of Oxford and 

 Cambridge. His scheme will provide no substantial livings. 

 The amount of fellowships, while ample for adequate study, will 

 not be so large as to induce the possessors to cling to them for a 

 livelihood, and, moreover, the fellows will be selected and not 

 ascertained by competition. The fellowships will be directed 

 mainly into the channels of scientific research. Graduates 

 desiring to become fellows will be required to state the class of 

 research they wish to pursue. 



The annual meeting of the Mathematical Association was 

 held on January 24, Prof. A. Lodge in the chair. The report 

 of the committee appointed by the Association to consider the 

 subject of the teaching of elementary mathematics, to which 

 reference has already been made in these columns, was referred 

 to in the council's report for the past year. Prof. Forsyth 

 was elected president for the forthcoming year, and Mr. A. W. 

 Siddons submitted the report of the committee on the teaching 

 of elementary mathematics, which, he said, had been criticised 

 as very conservative. The most immediate need was that 

 the preparatory schools should move in the matter, and 

 they should get the head-masters of such schools to adopt a more 

 modern treatment of mathematics. It would not be done in the 

 public schools unless the boys were taught from the beginning. 



