598 



NATURE 



[June 29, 191 1 



g('f<ihrlich, weiin dieselbcn hinrcichend fcinen Staub 

 liifern ; falls dieses aber nicht stattfindet— und dieser Fall 

 siheint in der That rccht hiiufijj vorzukommen— bieten 

 difselben wcnig Gefahr " (vi., 23, 24, 25). 



" Hiernach haben unsere Versuche die friiher ver- 

 breiteten Ansichten in diesem Punktc bestimmt widerlegt." 



In this case, also, the coal dust was taken from the 

 screens or from the mines, and employed without any 

 previous sifting or preparation of any kind. It was thus 

 of the same character as that employed in the Austrian 

 j^ailery, and therefore subject to the same drawbacks. In 

 by far the larger number of trials the strewing in the 

 gallery was only 10 m. in length, and the charge of 

 explos'ive was invariably 230 grams of black powder. 



It is therefore undoubtedly useful to have some of the 

 more exact numerical data established by the recent experi- 

 ments in regard to even a few classes of coal, such as the 

 liniii <)l cxplii-ihilit}- with decreasing volatile matter, on 

 thr oiir liaiul, aiiil with increasing incombustible mineral 

 matter on the other, although it is quite certain that both 

 of these limits must necessarily be profoundly modified by 

 the presence of more or less firedamp in the air, and by 

 the higher temperature, lower capacity for heat, and more 

 active oxidising properties of the oxygen in the air under 

 the compression existing in the condensed wave of an 

 ( xplosion in the workings of a mine. 



But it requires very little consideration of the number 

 of natural factors that vary to show that even the most 

 elaborate series of experiments that could possibly be 

 carried out can only touch the outer fringe of the subject. 



In these circumstances it is to be hoped that in accepting 

 the loan of the e.xperimental tube and other appliances at 

 .\ltofts from the colliery owners, and in constituting them- 

 selves and others into a committee for the purpose of 

 making experiments with them, the Royal Commission on 

 Mines will confine its attention to a few very definite 

 objects, and will, before everything else, including even the 

 treatment of dust in the main haulage ways, bear in mind 

 that the true solution of the coal-dust question lies in the 

 pnvention of explosions by the honest application of well- 

 kiu>\vn means, tliat is to say, of means applied in such a 

 manner as would, in liie opinion of the present writer, 

 vviio examined the scenes of the explosions in both White- 

 haven and Hulton Collieries, undoubtedly have saved the 

 lives of 480 ' men in 1910, and not in the slipshod way in 

 which the law has hitherto allowed. 



The siren song of the inventors, vendors, and advocates 

 of rescue appliances which, it is said, have never yet saved 

 a single life after an explosion, but have been the means 

 of losing many ; the trumpetings of those who are clamour- 

 ing for the establishment of " zones," and even the 

 counsels of those who beseech us to have mice and little 

 birds ready to test the afterdamp, seem to have almost 

 completely distracted attention from the real point at issue 

 for several years past. Even the Royal Commission on 

 Mines seems to have allowed itself to become entangled, 

 not only in the Circean alliance referred to above, but to 

 some extent also in a Charybdic whirlpool of supposed 

 palliative suggestions. 



As has been often said before, great explosions occur 

 exclusively in dry and dusty mines, and are invariably 

 begun either by the intentional detonation of an explosive 

 (shot-firing) or by the accidental ignition and explosion of 

 a certain volume of inflammable gas. If the coal dust 

 lying within a certain radius of the one presumed centre 

 of disturbance or the other were always rendered suffici- 

 ently damp beforehand to prevent it from being raised up 

 into the air by the subsequent blast, a great explosion 

 would be impossible in any mine. One efficient means of 

 attaining this end consists in spraying water from the 

 nozzle of a flexible hose attached to the branch of a water- 

 main or to a tank on wheels containing water and com- 

 pressed air. The means is, therefore, " not in heaven " — 

 neither is it beyond the sea — " but is very nigh " — is, in 

 fact, already in use in many of our mines. 



If the Royal Commission on Mines were only strong 

 enough and independent enough, it would specify cate- 

 gorically in u'Jiaf manner (by means of pipes or water- 

 tanks) and to what extent (distance or radius, and quantity 



1 Whitehaven Colliery, May 11, 136 ; Pretoria Pit, Bolton, December 21, 

 344- 



NO. 2174, VOL. 86] 



per unit of area) water must be applied in the cai>e of shot- 

 firing in order to render the operation quite safe, and 

 (shall we aLso add?) in the presence of accumulations of 

 inflammable gas ; it would insist with all the weight of 

 its Royal authority that the regulations which it recom- 

 mends be placed upon the Statute Book and be rigidly 

 enforced in the practice of every dry and dusty mine work- 

 ing coal with, say, 12 per cent, of volatile matter and 

 upwards, whatever may be the nature of its roof and 

 floor ; and it would add in the way of serious and 

 impressive ad.vice to all engaged in mines of this class 

 words of similar import to those employed by the great 

 Hebrew lawgiver in similar circumstances : 

 " And thou shall teach them diligently unto thy children. 

 And shalt talk of them when thou sittest in thine house, 

 And when thou walkest by the way, 

 And when thou liest down and when thou risest up. 

 And thou shalt bind them for a -sign upon thine hand. 

 And they shall be as frontlets between thine eyes, 

 And thou shalt write them upon thy posts, and on thy 

 gates." 



W. Galloway . 



ENTOMOLOGICAL PAPERS. 

 A MONO a batch of papers received from the Entcmo- 

 "'*• logical Bureau of the U.S. Department of Agri- 

 culture, perhaps the most generally interesting is one, by 

 Mr. F". C. Bishopp, on the distribution of the Rocky 

 Mountain spotted-fever tick (Dermacenior venustus). Now 

 tTiat the fever is known to be principally, if not exclusively, 

 transmitted to man by the tick, the determination of the 

 distributional area of the latter has become a matter of 

 importance. Western Montana is the district where the 

 disease occurs in its most virulent form, but it is also met 

 with, although in a less severe type, in parts of Idaho, 

 Wyoming, Utah, and Nevada, and these areas coincide to 

 a great extent with the maximum abundance of the tick, 

 the whole range of which includes parts of Washington, 

 Montana, Oregon, Idaho, Wyoming, Nevada, Utah, 

 Colorado, and a small tract in New Mexico. In its earlier 

 stages the tick infests small mammals, but later on 

 migrates to the larger domesticated species, and it is in 

 districts where the latter abound and brush-wood is 

 plentiful that it attains its maximum develc^ment. Un- 

 fortunately, the disease appears to be spreading. 



In a second pamphlet Mr. T. L. Patterson records the 

 results of investigations into the habits of the larv^ of 

 certain flies of the family Sarcophagida; in relation to the 

 pernicious gipsy moth (Porthetria dispar). As a rule, the 

 sarcophagid maggots feed only on decomposing pupae of 

 the moth, but consignments from Europe and Japan 

 suggest that the larva; of some of the flies may be truly 

 parasitic on the pupae, in which case it is hoped that an 

 additional means of controlling the ravages of the moth 

 may be obtained. 



Other pamphlets deal with the " asparagus-miner '" 

 {Agromyza simplex), insects afTecting stored grain, and 

 the one-spray method of checking the codling-moth and 

 th? plum-weevil. 



According to the report of the Dominion entomologist, 

 Dr. C. G. Hewitt, issued in the annual Report on Experi- 

 mental Farms for 1909-10, Ottawa, a new Destructive 

 Insect and Pest Bill was introduced during the period 

 under review into the Canadian Parliament. The necessity 

 for such legislation, owing to the rapidly increasing volume 

 of foreign trade, was pressing, as it was essential to 

 provide means against the introduction, or reintroduction, 

 of such pernicious species as the San ]os6 scale and 

 woolly aphis, and the brown-tail and gipsy moths. Thre 

 brown-tail moth, introduced some years ago, is still the 

 most imjx>rtant enemy against which the Entomological 

 Department has to fight, and it is essential that every 

 possible means should be taken to prevent its spread, as 

 otherwise the financial and other losses caused by its 

 devastations will be appalling. It is satisfactory to learn 

 that there were no serious injuries caused during the year 

 by insects harmful to cereal crops, which form the staple 

 of Canadian agriculture. 



Interesting observations on the duration of life in Saniia 

 cecropia, a common American moth, are recorded by Mr. 



