546 



NATURE 



[April lo, 1879 



formed (the third round the entire province), with orders to kill 

 whoever tried to break the blockade and did not stop at the tirst 

 summons ; and some individuals were actually killed. But I 

 cannot think an entire country is able to protect itself thus. 

 Examination of passports would be excellent if those who de- 

 liver passports and certificates of health were angels. But the 

 Russian functionaries are men, and think like men. The im- 

 possibility of always getting true certificates of origin has been 

 seen in the case of the cattle plague. I consider, however, that 

 pressure should be exerted on Russia to form a blockade of the 

 infected districts. And especially it should be seen to, that the 

 returning Russian army does not bring any pestilential germs with 

 it. As to restrictions on communications by land, the greatest 

 of these ar e ineffectual for the end desired. 



I cannot give an opinion as to whether the matters which are 

 now forbidden to be imported into the German Empire may 

 propagate the plague. The negative does not seem to suffice. 

 We know that the skin or hair of an ox affected with carbuncle 

 may engender contagion after several months in di^tant countries ; 

 we should not forget this, and we have not the right to say that 

 garments, linen, bedclothes, &c., are perfectly innocuous. 



A word on two points relative to disinfection. On Prof. 

 Pettenkofer's advice, the German empire has decided for sul- 

 phurous acid as a means of disinfection. I que-;tion if this 

 substance would penetrate linen, clothes, wool, &c., in such a 

 complete way as to annihilate all germs. In my opinion a 

 better plan is disinfection of clothing, &c., by dry heat in a 

 chamber surrounded by steam-pipes, the temperature being 

 raised to 120° C. or more. This plan is more ratio nal and easy, 

 and damages the objects least. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



In the Cambridge Senate, last Saturday, Mr. Balfour, a recent 

 examiner in the Natural Science "Specials" for the B.A. 

 degree, spoke of the schedule for botany, to which we referred 

 recently, as extremely unsatisfactory and incomplete; histology 

 was altogether neglected, physiology was very unsatisfactorily 

 dealt with, and cryptogamic botany was almost entirely omitted. 

 He was in favour of an examination in elementary biology being 

 substituted, and practical work being i-equired. Physiology 

 should be made a separate subject. Prof. Humphry spoke in 

 favour of reducing requirements in schedules to the narrowest 

 ran;e, in order to make natural science attractive to men. Mr. 

 Trotter thought the schedule in botany an absurdly small repre- 

 sentative of a year's work for a man supposed to have no other 

 definite study. Mr. Bettany found fault with the present con- 

 stitution of the Board of Natural Science Studies, which dealt 

 with too many subjects, each being insufficiently represented by 

 men engaged in teaching and research. No doubt it is hard for 

 many to realise that biology has very many distinctive aspects, 

 each of which mu~t be represented by proficiency in them to pre- 

 vent inju-tice and injury to scientific progress. Hindrances also 

 arise from the fact that many of our present leaders and directors 

 of study were developed before the full reco^^nition of cell-study, 

 embryology, and the like, as the basis of sound biology. 



Dr. Alexander Dixon, Professor ' in the University of 

 Glasgow, has been elected to the Professorship of Botany in the 

 University of Edinburgh, vacant by the resignation of Dr. 

 Balfouf. 



SCIENTIFIC SERIALS 



The Archives des Sciences Physiques el Naturelles (Febniary, 

 1879), contain the following papers of interest: — On the hydrocar- 

 bons obtained through the action of methyl-chloride upon benzole 

 in the presence of ammonium chloride, by MM. E. Ador and A, 

 Rillet. — On the theory of timbre and particularly on that of 

 vowels, by Dr. Schneebeli.— On the scientific principles of the 

 fine arts ; essays and fragments on the theory, by E. Brucke, 

 followed by remarks on optics and painting, by H. Helmholtz. 

 — On some rare mosses, by J.' E. Duby. — Stratigraphical study 

 of the souih-we-tern part of the Crimea, by E. Pavre. — Natural 

 history of batrachia, by Fr. K. Knauer. — On a ogamic ferns 

 and on apogauiy generally, by Prof. A. de Bary. — On the prolifica- 

 tion of the fruit of mosses, by Dr. N. Pringsheim. — On poly- 

 embryony, by Dr. Ed. Strasburger. 



The Journal de Physique (March) contains the following 

 more important papers : — On spectroscopes with direct vision 

 and great dispersion, by M. Thollon. — On the logograph, by 

 M. Barlow. — On a new phenomenon of static electricity, by M. 

 E. Duter. — Note on spectrophotometers, by M, A. Crova. — On 

 the vibratory motion generated in the air and in space by elec- 

 tric sparks, by E. Mach. — On the electricity of air, by Rob. 

 Nahrwold. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, March 13.—" On the Influence of Coal-dust 

 in Colliery Explosions." No. 2. By W. Galloway. Commu- 

 nicated by Robert H. Scott, F.R.S., Secretary to the Council of 

 the Meteorological Office, 



The first experiment is made with a very simple apparatus 

 consisting of a continuous pipe about 18" in diameter, which 

 conducts a small portion of the return air from the point at which 

 it is ejected into the atmosphere by the ventilatmg fan, to a 

 convenient spot on the level of the surface, where it escape^ as a 

 strong current, amounting to 1,251 cubic feet per minute. About 

 6 feet from its point of exit a lamp can be placed in the centre 

 of the current, and at a distance ot about a foot >till nearer the 

 origin there is a means of allowing coal-dust to fall into and mix 

 with the passing air. It is found that when the c )al-dust is 

 added the air becomes instantly iuflammable, showing that all 

 the return air in the workings may be easily brought into the 

 same condition by a sudden disturbance such as that caused by 

 a local explosion of fire-damp. 



The second experiment is intended to illustrate the effects of 

 an explosion of fire-damp in a dry mine containing coal-dust. 

 One part of the apparatus represents a gallery with coal-dust 

 lying on its floor as well as in the horizontal timbers, the build- 

 ings and other rough surfaces at its top and sides ; another part 

 represents a cavity in the roof containing an explosive mixture 

 of fire-damp and air. When the explosive gas is ignited the 

 flame sweeps down into the gallery, the disturbance raises the 

 coal-dust, and the results are exactly those that have been fore- 

 seen. The gallery is a wooden pipe 14 inches square inside, by 

 79g feet long. The explosion-chamber is a sheet-iron cylinder 

 lined with thin wooden laths ; it is 5 feet high by 15 inches in 

 diameter, and it stands vertically on the top of the gallery at a 

 distance of 5 feet from one end. Currents of air of different 

 quality can be made to pass along the gallery from the end next 

 the explosion-chamber, which can be isolated by means of a 

 valve, to the other end which is open to the atmosphere ; thus 

 the return air of the mine can be made to traverse it, or a current 

 of pure air, or a current of air mixed with any required propor- 

 tion of fire-damp. At the point where they enter the gallery 

 these air- currents are heated by a steam cylinder, which occupies 

 part of the space between the explosion-chamber and the nearer 

 end, so as to assimilate their temperature to that of the air in a 

 mine. The coal-dust is spread along the floor of the gallery, and 

 some is laid on shelves so that it may more easily mix with the 

 air when it is disturbed. 



The explosive mixture is made by admitting about half a cubic 

 foot of fire-damp into the explosion-chamber at its upper end, 

 while a corresponding quantity of air is allowed to escape 

 through a plug-hole at its lower end. The bottom of the ex- 

 plosion-chamber is separated from the gallery by a diaphragm 

 of paper during this part of the operation. After the requisite 

 quantity of fire-damp has been admitted, its volume having been 

 accurately measured so as to guarantee that the results will 

 always be the same, the mixture is effected by rapidly revolving 

 a small fan, situated at the top of the explosion-chamber, and 

 so constructed as to draw in air from the centre of the chamber, 

 and throw it out at the circumference. From the point at whic;' 

 the fan draws in its air a 4-inch pipe de-cends to near the botto; 

 of the explosion-chamber, and when the fan is revolved the air i- 

 drawn up through this pipe and discharged at the top of tlu 

 chamber, from which it finds its way again to the bottom, an 1 

 so on. The circulation established in this way is so rapid that 

 perfect mixture can be made in half a minute. The explosive 

 mixture is ignited by means of a spark from a powerful magneto - 

 electric niachire. 



When there is no cial-dust in the gallery the flame of the fire- 

 damp explosion does not extend further . than from 7 to 9 feet 

 from the bottom of the explosion-chamber." 



