300 



NATURE 



[January 26, 189^ 



well as in ordinary combustion, the oxidation of the car- 

 bonic oxide is effected by the interaction of the steam. 



4. Inert gases are found to retard the explosion wave 

 according to their volume and density. Within wide 

 limits an excess of one of the combustible gases has the 

 same retarding effect as an inert gas (of the same volume 

 and density), which can take no part in the reaction. 



5. Measurements of the rate of explosion can be em- 

 ployed for determining the course of some chemical 

 changes. 



In the explosion of a volatile carbon compound with 

 oxygen, the gaseous carbon appears to burn first to car- 

 bonic oxide, and afterwards, if oxygen is present in 

 excess, the carbonic oxide first formed burns to carbonic 

 acid. 



6. The theory proposed by Berthelot— that in the 

 explosion wave the flame travels at the mean velocity of 

 the products of combustion— although in agreement with 

 the rates observed in a certain number of cases, does not 

 account for the velocities found in other gaseous mix- 

 tures. 



7. It seems probable that in the explosion wave — 



(i) The gases are heated at constant volume, and not 

 at constant pressure ; 



(2) Each layer of gas is raised in temperature before 

 being burnt ; 



(3) The wave is propagated not only by the movements 

 of the burnt molecules, but also by those of the heated 

 but yet unburnt molecules ; 



(4) When the permanent volume of the gases is 

 changed in the chemical reaction, an alteration of tem- 

 perature is thereby caused which affects the velocity of 

 the wave. 



8. In a gas, of the mean density and temperature cal- 

 culated on these assumptions, a sound wave would travel 

 at a velocity which nearly agrees with the observed rate 

 of explosion in those cases where the products of com- 

 bustion are perfect gases. 



9. With mixtures in which steam is formed, the rate of 

 explosion falls below the calculated rate of the sound 

 wave. But when such mixtures are largely diluted with 

 an inert gas, the calculated and found velocities coincide. 

 It seems reasonable to suppose that at the higher tem- 

 peratures the lowering of the rate of explosion is brought 

 about by the dissociation of the steam, or by an increase 

 in its specific heat, or by both these causes. 



10. The propagation of the explosion wave in gases 

 must be accompanied by a very high pressure lasting for 

 a very short time. The experiments of MM. Mallard 

 and Le Chatelier, as well as the author's, show the pre- 

 sence of these fugitive pressures. It is possible that data 

 for calculating the pressures produced may be derived 

 from a knowledge of the densities of the unburnt gases 

 and of their rates of explosion. 



NOTES. 



The forty-sixth annual general meeting of the Institution of 

 Mechanical Engineers will be held on Thursday evening and 

 Friday evening, February 2 and 3, at 25, Great George 

 Street, Westminster. The chair will be taken by the president, 

 Dr. William Anderson, F.R.S., at half-past seven on each 

 evening. The annual report of the council will be presented to 

 the meeting on Thursday, and the annual election of the presi- 

 dent, vice-presidents, and members of council, and the ordinary 

 election of new members will take place on the same evening. 

 The following papers will be read and discussed, as far as time 

 permits : — Description of the Experimental Apparatus and 

 Shaping Machine for Ship Models at the Admiralty Experiment 

 Works, Haslar, by Mr. R. Edmund Froude, of Haslar (Thurs- 

 day) ; description of the Pumping Engines and Water-Softening 

 NO. I 2 13. VOL. 47] 



Machinery at the Southampton Water Works, by Mr. William 

 Matthews, Waterworks Engineer (Friday). 



Pkof. Cayley, we are glad to learn, is now convalescent. 



We greatly regret to have to announce the death of Mr. H 

 F. Blanford, F.R.S. He died on Monday at the age of fifty- 

 eight. 



Prof. Michael Foster, Sec.R.S., has been appointed 

 Rede Lecturer at Cambridge for the present term. His Rede 

 lecture will be delivered early in June. 



The Bill for the introduction of a standard time (mean 

 solar time of the fifteenth meridian) was read a second time in 

 the German Imperial Parliament on Monday. The measure 

 was accepted without much discussion. 



An excellent report on technical education in London has 

 been submitted to the London County Council by a special 

 committee appointed to investigate the subject. The report was 

 prepared by Mr. Llewellyn Smith, the committee's secretary, 

 and displays a thorough grasp of the essential conditions of the 

 problem. It is proposed that a Technical Instruction Board shall 

 be appointed, and that it shall consist of some members of the 

 Council, and of representatives of the School Board, the City 

 and Guilds of London Institute, the City Parochial Charities, 

 the Head Masters' Association, the National Union of Ele- 

 mentary Teachers, and the London Trades Council. The com- 

 mittee think that one-third of the amount derived from the beer 

 and spirits duties should be handed over to this body for the 

 provision of adequate technical instruction in all parts of 

 London. 



The French Minister of the Interior has established at Mar- 

 seilles, in connection with the university, an institute for 

 botanical and geological research, and a museum. The director 

 is Prof. Heckel, who, as well as a curator and a librarian, gives 

 his services gratuitously. 



In the year 1793 was published Christian Konrad Sprengel's 

 "Das entdeckte Geheimniss der Natur,im Bau und in der Befruch- 

 tungder Blumen," the work which first directed the attention of 

 naturalists to the contrivances which, in many flowers, render 

 self-pollination difficult, and promote the visits of insects to assist 

 cross-pollination. The copper-plate illustrations of this work 

 still maintain their character as among the best that have been 

 published in this branch of science. Sprengel was in many 

 respects a forerunner of Darwin, and centenaries have been 

 celebrated on slighter grounds than the publication of this work. 



The chief characteristics of the weather during the past week 

 have been its general mildness and dampness ; the day tem- 

 peratures have at times exceeded 50° in most parts of the 

 kingdom, but at night slight frosts occurred towards the end of 

 last week in Scotland and the south-eastern parts of England. 

 The distribution of pressure has been complex, a series of de- 

 pressions have passed over the coast of Norway from the west- 

 ward, while an anticyclone lay over the south-western parts of 

 our islands, the reading of the barometer in the south-west 

 being about an inch higher than in the north of Scotland. The 

 passage of the low-pressure systems in the north was accom- 

 panied by strong north-westerly winds and gales in Scotland, 

 with hail or sleet in many places. Owing to the disappear- 

 ance of the anticyclone from the continent, north-westerly 

 winds became prevalent over western Europe, and a rapid 

 rise of temperature occurred there, amounting to 30° in 

 Germany between the 20th and 21st instant. During the 

 last few days fresh depressions have approached our north- 

 western coasts, with increasing winds from the south-west, and 



