February 2, 191 1] 



NATURE 



437 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Naturb. 

 So notice is taken of anonymous communications.] 



Colliery Warnings. 



During the past thirty years, the Colliery Warnings 

 appearing from time to time in various leading news- 

 papers in the British coalfields have been vigorously, even 

 viciously, attacked by a few mining engineers and pro- 

 fessors of mining. Two excuses have been advanced as 

 an explanation of these onslaughts — warnings are held to 

 be an insult to the intelligence of miners, and, although 

 based upon recorded facts, they are diametrically opposed 

 to theory, to the common view, and to educated opinion. 

 It is the theory that forms the burden of a column article 

 on the subject in the Times of January 4, and it is the 

 theory which Prof. Henry Louis harps upon in N.\ture 

 of January 12, pp. 336-8. 



One of the most remarkable features of the various 

 discussions has been the refusal of the theorists to accept 

 any facts unless these can be made, somehow or other, to 

 support the common view. Of Darwin it has been said 

 that *' he would destroy his theor)- rather than ignore a 

 Tact." It is a pity that many prefer to adopt the opjxxsite 

 principle, and are ever ready to dismiss facts which do 

 not support popular beliefs. When definite facts are 

 stated showing that the Colliery Warnings are issued 

 during the periods when nearly all our mining disasters 

 occur, the usual retort is that the cases have little or no 

 bearing on the matter, and yet if a misstatement is made 

 as to the atmospheric conditions, the theorists claim that 

 the accident is one that supports their view. Newspapers 

 are a fruitful source of error, especially in scientific 

 matters. The melancholy fact is that, with all the 

 " education " of the past fort}- jears, people appear to be 

 more ready than ever before to swallow the most ridiculous 

 statements appearing in the Press under the guise of 

 scientific information. 



Here is Prof. Louis entering upon a crusade against 

 Collier\- Warnings because they are not in accordance 

 with his theon,-. Of course, the first impression the 

 general reader entertains is that the professor has mastered 

 the meteorology of the subject, but when, as a witness 

 before the Royal Commission on Mines, on May 27, 1908, 

 he was asked if he was acquainted with the official daily 

 meteorological reports, his reply was : " I have seen them, 

 but I am not familiar with them," an admission which 

 puts him out of court. Books of newspaper cuttings, on 

 the other hand, are far more entertaining than drj' official 

 reports, and it does not require much research to alight 

 upon definite statements that colliery explosions have 

 occurred under a low or rapidly falling barometer. The 

 most glaring of them is connected with the greatest mining 

 disaster the world has ever known — the explosion in the 

 Courriferes mine, within a few minutes of 7 a.m. on March 

 10, 1906, when about 1200 miners perished. Prof. Louis, 

 'loubtless, read the statement in the Colliery Guardian, 

 the organ of the mining engineers, that that frightful 

 calamity was accompanied by a " pronounced fall of the 

 barometer." The assertion fitted in exactly with the 

 theory, and therefore there could be no possible objection 

 to it. The statement, however, was most inaccurate. .\t 

 the ver}.- moment that the pit blew up. observations were 

 being taken all over France and neighbouring countries, 

 and almost before it was known that the disaster had 

 occurred, the Bulletin International du Bureau Central 

 Meteorologique de France had been prepared showing the 

 existence of a well-marked area of high pressure right 

 over France ; the barometer had been rising throughout 

 the previous night, it was rising at the time of obser\-a- 

 ;ron, and subsequent reports showed that it continued to 

 tise for some time after the explosion. No amount of 

 iugglinfj with what was said in the papers can get over 

 ihe cold, dry record of facts. The official information 

 '« public property, which Prof. Louis and all who support 

 hint can consult at leisure and at trifling cost. 



l< Mav and June. 1910. rpaders of the Scotsman were 



treated to a discussion of the subject, one of the critics 

 giving the worst case in his long experience of such an 

 issue of damp in a mine in the east of Scotland '* that 

 the airways, &c., became so foul, the miners had per- 

 force to leave off work and clear out." This dangerous 

 outburst was said to be associated with the glass falling 

 an inch in the course of a few hours. It agreed precisely 

 with the popular notion of the external fitness of things. 

 In a subsequent communication the critic, to dispel the 

 doubt about the barometer having dropped at an unheard- 

 of rate, supplied readings said to have been obtained from 

 the Kew and Glasgow records. Unfortunately for the 

 theorists, the Glasgow values show that the decrease of 

 pressure on each of the two occasions relied upon was 

 exactly an inch less than was stated by the critic, the 

 barometer standing very high, in the first case perfectly 

 steady, changing only 0-005 '""^^ C*^^ 1-005 inches) in six 

 hours, and in the second case declining 01 12 inch (not 

 I- 1 12 inches) in six hours. These imaginary- falls of more 

 than an inch in six hours will have got into many a scrap- 

 book for future reference. 



How determined the theorists are not to attach any 

 weight to evidence which is unfavourable to them is well 

 illustrated by the rash condemnation of the Seaham 

 records by a leading supporter of the low-barometer 

 idea : — " .As to Mr. (5)rbett's figures, they have given us 

 much amusement, as he got results flatly contradicting 

 simple scientific principles. The Germans at Saarbriicken 

 similarly." Facts obtained by careful observers in 

 different countries are thus not entitled to consideration ; 

 they only deserve to be laughed at because they are at 

 variance with preconceived notions. 



Prof. Louis and his supporters are afraid that if they 

 give way on this question, a terrible fate awaits the 

 world — nothing short of casting Boyle's law to the scrap- 

 heap. But they can rest assured that no such dire 

 calamity is indicated. Boyle's law will for ever remain 

 unassailable ; what must go by the board and to the scrap- 

 heap is the method adopted by the low-pressure theorists 

 to support their views. Who first started the curious idea 

 that the barometer falls at the rate of 001 inch per 

 minute is not known, but it is the rate used by many 

 writers here and abroad. It was adopted by the Royal 

 Commission of 1879-S6, by Sir Frederick .\bel, by the 

 Colliery Guardian, and others, to show that an acre goaf 

 charged with a yard in depth of gas would foul a 

 ventilating current of 1000 cubic feet per minute to the 

 extent of 4-4 per cent., and the current is consequently 

 nearing the explosive point, which is from 5 per cent, to 

 7 per cent, of fouling. There are two ver>' serious objec- 

 tions to this conclusion. In how many mines in the 

 United Kingdom do the Government inspectors consider 

 1000 cubic feet of air per acre of gas as ample for 

 ventilating purposes? Has anyone ever known, within 

 the temperate zone, falls of the barometer at the rate of 

 0-6 inch per hour, or 14-4 inches per day? The alleged 

 fall of an inch in six hours at Glasgow, referred to above, 

 is a mere nothing compared with the stupendous rate 

 beloved of mining engineers. Continental experts who 

 .have studied the subject have decided that 004 inch 

 (i millimetre) per hour is a ven,- rapid fall. A rate of 

 006 inch per hour is far from being a common occur- 

 rence, and intervals of years may pass between falls of so 

 much as o-i inch in an hour. To prove their case, the 

 theorists have adopted a rate which is fifteen times greater 

 than a very rapid fall. Even if we apply 006 inch per 

 hour, or 0001 inch per minute, and keep to the 1000-foot 

 ventilating current, it reduces the fouling from 44 per 

 cent, to 044 per cent., a proportion which the firemen 

 would have very great difficult}- in detecting. There is 

 here no violation of Boyle's law, which teaches us that 

 the expansion of the gas is proportional to the diminu- 

 tion of pressure, not ten or fifteen times greater. In 

 general terms, it may be stated that with a nc«-mal 

 ventilating current no diminution of pressure in our lati- 

 tudes is sufficiently great to bring out from the open goaf 

 a volume of gas large enough to foul the ventilation to the 

 explosive point. 



Now as to the high-pressure side of the question. Prof. 

 Louis strongly objects to Warnings against danger during 

 anticyclonic periods, for they upset his teaching ; but the 

 note in Nature of December 29 last, p. 277, shows that 



NO. 2153, VOL'. 85] 



