242 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[August 



the walls of one of (he passajps ; an effect which conld scarcely be con- 

 ceived without supposing that the flame played for some time upon it with 

 the intcnsily of a blow. pipe flame. The surface of coal thus acted upon 

 was so considerable that the amount of explosive gases e\olve(l (luring this 

 eoUing must have been far fiom insiKnificanl, and may liave aided llie ex- 

 plosion itself. Atl<\ to this, lliat the lirst effect of llie explosion is to blow 

 up and ignite the immense quantity of coal dust lyin^ about the pit, and 

 not only produce from it an evolution of gas, but also occasion the produc- 

 tion of much carbonic acid. And it cannot escape attention that the whole 

 fobject becomes involved in much complexity. It is known tliat a certain 

 mixture of air with carburetti<l hydnigen prevents its ascenilibiliiy ; and, 

 in the case of pure carburetied hydroj;en, the proporlimi has been ascer- 

 tained to be not less than 15 times its own bulk. IJut the variation in 

 coinposilion of the lire-damp of ddferent mines, the uncertain modes of lis 

 issue, and tlie absence of any ready means of ascertaining its quantity, pre- 

 vent any general rule being given as to the amount of air which should be 

 thrown into mines to prevent the atmosphere ever attaining the explosive 

 slate. All this must be determined by practice to suit tlie varying condi- 

 tions of different mines. It is certain that impnivemenls might be iiiade 

 on the rude methods now in use for effecting tlie necessary mixture. 'I he 

 fire damp being, from its lightness, at the top, is not quickly, influenced liy 

 the current of cold heavy air descending the downcHst shall, and ciiculal- 

 iug through the passages. It is therefore not uafreqnenl to see colliers 

 flapping Iheir jackets among this light gas, so as to dilute it wiih the sulli- 

 cieut quantity of air,and ihusdislurh the train of communicating gaswhi.h, 

 iu a fijul stale, may connect two dangerous parts of a pit. Jlechaiucal 

 contrivances, such as fanners, would more efficaciously produce the result 

 than the ineflicient extemporaneous means referred to ; but, in general, buch 

 arrangements are only necessary when, fnmi a defective veulilatiiin, the 

 current of air througli the pit is not suflicienlly strong. 



Various artificial means had been proposed to facilitate the withdrawal 

 of fire-damp from a pit. Suggestions have been made to take advantage 

 of the lightness of the gas by favouring its ascent to the upper parts of the 

 pits, and drawing it off by special air ways. Pipes let do«n into the 

 •wastes have been proposed for the same purpose, while other suggestions 

 have been made of pipes to blow in air at the tops of the passages, so as 

 to cause the dilution of the gas. 



We do not slop to consider these plans, because, as we have already 

 stated, the condiiions under which coal is workeil are so numerous, that a 

 plan which might prove useful in one pit would be wholly inapplicable 

 and sometimes positively injurious in another, and the legislative applica- 

 tion of any one plan might prove highly prejudical to this great branch of 

 national industry. 



In 1S35, a Select Committee of the House of Commons was appointed 

 to inquire " into the nalure, cause, and extent of those lamentable catas- 

 trophes from explosions which have occurred in the mines of Great Bri- 

 tain, wilh the view of ascertaining and suggesting ih- means of preventing 

 the recurrence of similar accidents." Numerous witnesses were exam- 

 ined before this Committee, a body of important evidence colleited, and a 

 report published in the same year,— a report repl"te with valuable inform- 

 ation, and to which we would wi^ll to refer for ample details connected 

 with the general mode of working collieries, especinlly in the uurlh of 

 England. The Committee observe, on the subject of colliery explosions, 

 that while the loss of interrupted trade by these accidents is enormous, 

 " it is nevertheless rather with reference to the cause and iulerest of hii- 

 manily than in a pecuniary point of view that this inquiry lias assumed its 

 great importance." This Commillee did uol recommend any remedial 

 measures. 



The difficulty experienced of obtaining accurate information respecting 

 the number of lives lost from colliery explosions within a limited period is 

 nearly as great at the present time as it was in 183.5. And it should be 

 borne in mind that the number of lives lost by the great explosions, those 

 which chiefly become known and arrest public attention, by no means 

 affords a correct view of the collective loss of life sustained by colliery 

 explosions generally, including the minor accidents not commonly heard of 

 beyond limited districts ; neither does it represent the injury sustained by 

 these explosions, short of the loss of life, but from which many persons 

 are more or less disabled. 



The Committee were enabled to ascertain that during the 25 years pre- 

 ceding these inquiries 2 070 persons had perislnd from colliery explosions; 

 and they considered this number much underrated. During the last 10 

 years the rale of loss of life from this cause has certainly not diminished. 

 The experience of the past year has shown that considerably more than 

 100 persons have been known to have thus perished. 



It has so unfortunately happened tiiat, during the few months we have 

 been engaged upon this inquiry two explosions, one at Jarrow in Durham, 

 and the other at Kisca, in Monmouthshire, have together deprived 7ti per- 

 sons of their lives, 41 having perished at the former and 3.5 at the latter. 



15y direction of Sir James Graham and the Earl of Lincoln, we were 

 eonimissiooed to ascerlain the causes of both explosions. It so occurred 

 that, being at that time in the south of Irelaml, engaged on the duties of 

 the geological survey, Sir Henry de la Beihe could not reach Jarrow in 

 time for the inquiry, and tlierefore the investigation into the cause of the 

 •xplosion at Ihal place devolved upon Dr. I'lajfair, who, under these cir- 

 cumstances, availed himself of the services of Mr. David Williams, at 

 that time one of ihe geologists attached lo the geological survey of Great 

 Britain, and well skilled iu coal mining, but now iu the service of the 



East India Company, examining the coal resources of India. The result! 

 of this inquiry are given in the accompanying report by Dr. Playfair. 



Iiiinieilialely afier the explosiim at Itisca on the 14lh of January, 1840, 

 instructions were again received lo proceed without loss of time to Ihat 

 colliery. Dr. Playfair being, however, so enjjaged upon duties in London, 

 that he could not readily proceed to liisca, the investigation was under- 

 taken by Sir Hi nry de la Heche, aided by Mr. Warrington Smylh, mining 

 geologist to the geological survey of Ihe Uniled Kingdom, who was m 

 every respect qualified for such an inquiry. The accompauyiag report 

 contains the results of this investigation. 



During these inquiries it became very important carefully to consider 

 the kinds of lights employed in collieries, and the usual regulations re- 

 specting them. The subject was not new to us. since for more than 25 

 years the mode of working collieries in different parts of the I niled King- 

 dom, as also on the conliueiit of Europe, had engaged the attention of one 

 of us. On the subject of safely lamps, of lighting generally, and of the 

 regulations connecled with it, the Committee of 1B35 collected a Urge 

 amount of evidence, mure especially regarding our northern collieries. Id 

 the report of Ihe South Shields Coinmiilee of 1843 there is also much in- 

 format. on on this head. To these reports, therefore, we would wish to 

 refer for suliicieiit information on the subject. 



The Cuiiiiiiittee of 183.5 pointed out ihat more persons Lad lost their 

 lives from colliery explosions for the IS years succeeding the introduction 

 of the Davy sal'ety lamp in 1810 than in the 18 years preceding the inven- 

 tion, and accounted for this fact by the working of numerous " fiery" 

 seams of coal, which had, in consequence of the assumed security of that 

 lamp been undertaken, and by the abandonment of many precautions con- 

 sidered requisite when candles were commonly employed in collieries. 



As much doubt has been thrown upon the real safety of the Davy lamp, 

 it is but justice to the memory of Sir Humphrey Davy to stale Ihat he was 

 perfectly aware that, if a proper mixture of fire-damp and common air 

 were thrown against the lamp with suflicient force to project the flame upon 

 the gauze cylinder, it might communicate with the flame, and cause explo- 

 sion. iMr. liuddle, in his evidence (Iteport of tlommitlee of 1635, Nos. 

 2,220 and 2, 227), clearly shows this to have been the case. He mentions 

 an experiment at Mortou M'est Pit, were a very powerful blower from the 

 shaft was tried with the lamp, when the flame passed and the blower wa» 

 tired. Sir Humphrey Daiy then, addressing Lord Durham, and many 

 other ptrson.s who were present, said, " Now, gei.tlemen, you see the na- 

 ture of the d.inger to which you are exposed in using the lamp, and I cau- 

 tion you to guard against it in Ihe manner I have shown you. This is to 

 show the only case iu which the lamp will explode; and I caution and 

 warn you not to use it in any such case when you can avoid it without 

 using the shield." The shield recommended was one of tin, inside the 

 cylinder, to prevent a current of fire-damp from actmg on the flume. Mr. 

 liuddle stated before the Committee that in the lamps used in the collieries 

 under his niauhgenient the shield passed from oue-half to two-thirds round 

 Ihe inside of the cylinder, and, being bright, reflected the light lo such an 

 extent as to be more advantageous than a glass cylinder inside that of 

 wire gauze, a coutrnance often recommended to obviate the risk of cur- 

 rents of fire-damp. 



Dr. Peieiia, at the request of the Committee of 1S33, experimented 

 upon many lamps before them, and passed the flanie through all those 

 tesled, except that of iMessrs. Upton and Itoberis. The experiments have 

 beeu repeated at llie iMuseum of Economic Geology, by Dr. Pereira and 

 by ourselves, with the ordinary Davy lamp, and with ihe same results. 



Tliere can, therefore, he very little doubt that the flame cau pass, and 

 explode file-damp adjacent, if the current be sufficiently strong, and no 

 pioiection be afforded either by a metallic shield or by an internal glass 

 cylinder. I'he tjuestion as to the amount of current required seems not so 

 well ascei'laiued. Mr. ISuddle considered that the blowers would rarely 

 be found strong enough. Mr. Siephenson supposed that many accidents 

 may have happened by the falling of llie roof producing a sudden rush of 

 explosive fire-damp. It will be obvious that the same effect might be pro- 

 duced by the careless swinging of the lamp with the required velocity 

 through an explosive mixture ol fire-damp and air, or from the lamp being 

 so jerked out of a collier's hand, by an unlucky fall, that the cylinder pre- 

 sented the necessary front to the same compound. 



Without desiring, in the slightest degree, to cast unnecessary doubt OB 

 the salely of the Davy lamp, since we consider its cautious use an 

 immense boon to coal mining, and belie\e Ihat much additional security 

 is obtained by the proper use of the original Davy, or of its im- 

 provements, it can scarcely be denied that far more care in the use of 

 safely lamps is needed than is commonly employed. Although shields or 

 glass cylinders are used in some localities they are uever employed ia 

 others; and the bare siugle cylinder of wire gauze, uot always properly 

 maniifaclureil, is llie only form lu which Ihe Davy lamp is known. And 

 it should be observed that, with a few local exceptions, the Davy lamp is 

 that commonly employed. Numerous iiiodiDcalions, and in some cases 

 improvenients. of llie safety lamp have been made, but, either from the 

 expense, or want of simplicity lu management, have never come generally 

 into use. 



The colliers, by Iheir usual mode of carrying Ihe common Davy lamp, 

 certainly, under ordmaiy ciicumstances, guard against the passage of any 

 curtenl of fire-damp sullicieiitiy strong to pass the flame, by placing the 

 lamp within their jacket flaps, or carefully prolecled in some other man- 



