504 



NATURE 



[April 2 s, 1872 



New Zealand (Trans. Zool. Soc, vol. iv., 1850), and sub- 

 sequently by Darwin to the incoming of new species, as 

 " the battle of life." He next entered upon the relation 

 of the present discoveries in Australia to the law of Geo- 

 graphical Distribution in the new Tertiary or Quaternary 

 periods of extinct and existing animals. 



The wombat was a more characteristic Australian form 

 of mammal than the kangaroo, for the latter is repre- 

 sented by species in New Guinea ; and species of 

 Phalangcr range farther from Australia, though still 

 bound to the same great natural, and mainly submerged, 

 division of the earth's surface. But no kind of wombat, 

 recent or fossil, has been detected out of Australia and 

 Tasmania. The present Continental kinds, and species 

 near akin to them, existed in Australia during a very long 

 period, reckoned by the terms of historical time, if we may 

 judge from the state of petrifaction of the fossils, and the 

 great depths at which some have been met with in well- 

 digging ; where, after 30 ft. or 40 ft. of black rich soil have 

 been bored through, such fossils occur at 100 ft. lower 

 down in sandy drift, which has been accumulated to that 

 or greater vertical thickness beneath the loam. On the 

 assumption that air-breathing animals perished in a 

 general deluge some 5,000 years ago, and that their dis- 

 persion then began anew from the exceptional few indi- 

 viduals preserved in the Ark, we must suppose the 

 wombats then living in Australia to have contributed 

 miraculously their pair or pairs to the Asiatic menagerie, 

 and to have been as miraculously restored to their proper 

 continent on the subsidence of the Noachian flood. 



It is neither creditable nor excusable that so great a 

 divergence should still be maintained, chiefly through 

 theological teaching, in the ideas of the majority of men 

 "of ordinary culture " as to the cause and conditions of 

 the distribution of living species over the globe, from those 

 suggested by the clear and multiplied demonstrations of 

 Science. On this topic the author referred to a paper in 

 "Annals and Magazine of Natural History," i S50, " On 

 the Gigantic Birds of New Zealand, and on the Geo- 

 graphical Distribution of Animals." 



THE CONNECTION BETWEEN COLLIERY 

 EXPLOSIONS AND WEATHER* 



A FTER a preliminary reference to previous papers on 

 -^~^ the subject, and especially to the diagrams published 

 by Mr. Joseph Dickinson, and by Mr. Bunning, of Ncw- 

 castle-on-Tyne, the authors of the paper referred specially 

 to Mr. Dobson's paper, published in the reports of the 

 British Association. They showed that the periodicity 

 alleged by him to exist in these explosions had no real 

 foundation in fact ; for, on plotting the dates of the ex- 

 plosions for the last twenty years in two ten-year periods, 

 very slight resemblance was seen between the two curves. 

 The number of accidents (all fatal ones) on which the 

 statement was based was 1,369. 



In the progress of this inquiry it had come out that the 

 number of serious accidents, involving the loss of ten lives 

 or more, had materially increased during the last five 

 years, the numbers being : — 



1851-55 . . 13. 1856-60 . . 15. 



1S61-65 . . 12. 1866-70 . . 11. 



These numbers appear to be well worthy of remark. 



For the special purpose of the paper, the continuous 

 records from Stonyhurst, one of the observatories in con- 

 nection with the Meteorological Office, were taken, and 

 the curves for the barometer and thermometer were 

 plotted for the three years, 1S6S-70. The records of fatal 

 explosions were obtained from the published reports of 

 the inspectors, while the dates of the non-fatal accidents 

 were obtained from the inspectors themselves, who, almost 



* "On the Connection between Colliery Explosions and Weather," by 

 Robert H. Scott, F R.S , and Mr. W. Galloway. Read at the meetirg of 

 the Rojal Society, April i8, 1872. 



without exception, rephed to the communications ad- 

 dressed to them, and furnished the desired information. 



Mr. Dobson, in his paper, having spoken of the explo- 

 sions occurring principally at the commencement of a 

 storm, the authors showed that it was not, in some cases, 

 until two or three days after the barometer had reached its 

 lowest point that the accident happened. They showed 

 also why, during a period of continued violent oscillation 

 of the barometer, the passage of each successive baro- 

 metrical minimum is not characterised by an equal num- 

 ber of explosions, the largest groups of accidents being 

 reported when a serious break occurred after a period of 

 calm weather. 



The eficct of a high temperature of the air in interfering 

 with ventilation, and especially with natural ventilation, 

 was also explained, and it was shown how the first hot 

 days in spring were marked by explosions. 



The actual dates of the explosions for the three years 

 in question were then compared with the meteorological 

 records, and it was shown that out of 550 explosions — 



266, or 48 per cent., might be attributed to the state of 

 the barometer ; 



'23, ,,22 „ to the state of the thermometer ; 



161, „ 30 „ remained unaccounted for on me- 



teorological grounds. 



The next point touched upon in the paper was the 

 action of a more or less impure ventilating current in in- 

 creasing the explosive character of the air in all parts of 

 the pit, and possibly in causing an explosion in a place 

 which would have remained safe had the ventilating 

 current itself remained pure. It was shown how, when 

 an explosive mixture had been formed in places and under 

 conduions similar to those described, some time, possibly 

 several days, must elapse before the contents of such an 

 accumulation of dangerous gases shall have been rendered 

 innocuous again. 



The effect of warm weather in stopping natural ventila- 

 tion was explained. The natural temperature of a mine 

 of the depth of 50 fathoms being 55°, that of one of the 

 depth of 200 fathoms 70°, and so on (speaking generally), 

 it was shown that if the temperature of the air rose to 

 55° natural ventilation must cease in shallow pits, and 

 similarly in other cases. Accordingly, if a warm day 

 occurs in the cold season of the year, and the furnaces 

 are not in action, an explosion is very likely to occur. 



These statements were illustrated by one instance of 

 a fatal explosion, the cause of which had been declared 

 by the inspector to be inexplicable, the pit having "strong 

 natural ventilation." It appeared, however, that the ex- 

 plosion occurred on a warm day, while the inspector 

 visited it twice on colder days after the explosion ; so 

 that the state of ventilation which he witnessed had no 

 reference to that which must have prevailed when the 

 accident happened. 



The paper concluded by stating that it appeared that 

 the evidence fairly justified the view that meteorological 

 changes are the proximate causes of most of the accidents, 

 it being remembered, as has before been observed, that 

 the records contain no account of the number of times 

 when the pits have been loo dangerous for the men to go 

 down, and so explosions have not happened. 



Whatever be the meteorological changes, it is absolutely 

 necessary to keep a most careful watch over the amount 

 of air passing through the workings. 



Thirty years ago George Stephenson said, in a letter to 

 the South Shields Committee, referring to explosions : — 

 " Generally speaking, there has been some fault in the 

 ventilation of the mines when accidents have occurred ; " 

 ancl the same opinion is held by many of the most e.v:- 

 perienced authorities at the present day. In this matter 

 the one cry, whether we look to security against explosion, 

 or to the aftbrding to miners an atmosphere which they 

 can breathe without injury to health, is " More air I" 



