April 15, ib86j 



.NATURE 



ordinaiy Clanny lamp will almost certainly cause an explosion 

 in a current having a velocity of 600 ft. per minute. A Stephen- 

 son lamp will frequently cause an explosion in a current with a 

 velocily of 800 ft. per minute. From the information supplied 

 to us by your Majesty's Inspectors of Mines and others, currents 

 having velocities of more than 400 ft. per minute are now fre- 

 quently found in working places. The currents sweeping long 

 wall-faces have very often higher velocities, in main airways 

 current-velocities approaching 2,000 ft. per minute are recorded, 

 and considerably higher velocities are encountered at regulators 

 and in narrow |ilaces, or when large falls occur. It is thus obvious 

 that, in the present improved ventilation of collieries, ordinary 

 Davy and Clanny lamps have ceased to afford protection from ex- 

 plosion, and that the Stephenson lamp, though more secure tlian 

 the two former, cannot be relied upon. We felt it our duty at 

 an early stage of our investigation to draw the attention of the 

 Secretary of State to the danger attending the use of the ordi- 

 nary Da\-y and Clanny lamps, and our subsequent experiments 

 have made this danger still more conspicuous. We have no 

 hesitation in stating that these lamps should be prohibited, unless 

 they are inclosed in cases capable of effectually preventing the 

 gauze from being exposed to the full force of the current of air. 

 Many lamps now exist which are able to resist, in highly ex- 

 plosive atmospheres, current velocities up to and even exceeding 

 3000 ft. per minute, at all events for several minutes. Ample 

 time is thus obtained for bringing into operation a "shut off" 

 appliance for the extinction of flame produced both by the 

 illuminant and by ignited gas within the lamp. We consider 

 that all safety-lamps should be provided with such an appliance. 

 Four lamps seem to us deserving of special attention, as com- 

 bining a high degree of security with fair illuminating power 

 and simplicity of construction. They are Gray's lamp, Mar- 

 saut's lamp, the bonneted Mueseler lamp, and Evan Thomas's 

 modification of the bonneted Clanny lamp, described as No. 7 

 in our report. In our experiments the last lamp has given upon 

 the whole the best results. It will be seen, however, from our 

 experiments that many other lamps exist which are simple in 

 construction, and almost, if not quite, as safe as the above. 

 They generally, however, yield an inferior light in consequence 

 of the flame being surrounded by gauze, but from this method of 

 construction they derive the advantage of not being entirely de- 

 pendent on glass for their security. To make a particular lamp 

 compulsory would be unwise, as calculated to throw dil^culties 

 in the way of introducing improvements which will no doubt 

 arise in the future, but we think it desirable that some control 

 should be exercised in reference to the description of lamps 

 employed in coal-mines, and that only those lamps should be 

 used which are authorised from time to time by the Secretary of 

 State. A lamp may be of the safest pattern and yet small 

 defects in the fitting of its parts may entirely deprive it of 

 its power of affording protection. In preparing a large 

 number of lamps for use in a mine it may happen, even 

 with the greatest care on the part of the lamp-men, that 

 a lamp in an imperfect condition may be allowed to pass. 

 The detection of these imperfections by simple inspection is 

 in many cases almost impossible, and we are convinced 

 that the only way of avoiding the introduction into a mine 

 of a dangerously imperfect lamp is to test every lamp in an 

 explosive mixture of air and some inflammable gas before it is 

 allowed to descend the shaft. Though we have good reason to 

 believe that the practice of surreptitiously opening safety-lamps 

 in the workings is much less prevalent than formerly, it is still 

 necessary that such lamps should be locked. We have ex- 

 amined many appliances for this purpose, and we consider that 

 the plan of fastening the oil vessel to the other part of the lamp 

 by a riveted lead plug, impressed at each end with marks or 

 letters varied from time to time, is the simplest, the most efficient, 

 and the one most likely to lead to the detection of any attempt 

 to tamper with the lock. The power and uniformity of illumina- 

 tion given by a lamp can be notably improved by using, as the 

 illuminant, vegetable or animal oil mixed with about one-half 

 of its volume of a petroleum oil of safe flashing-point. The use 

 of petroleum spirit or benzine as the illuminant in safety-lamps 

 instead of vegetable or animal oil, is attended with some advan- 

 tages, but it is also liable to introduce new sources of danger. 

 Special care is needed in the filling and trimming of lamps, and 

 in the arrangement of lamp rooms, to avoid the ignition of the 

 highly explosive mixture formed by air with the vapour arising 

 from this spirit. The selling of petroleum spirit, or of spirit 

 of similar character as to volatility, under designations which are 



calculated to mislead in regard to the nature of the illuminant, 

 is a proceeding fraught with danger, unless all vessels'containing 

 such illuminants bear a prominent label indicating the dangerous 

 nature of their contents. Stringent regulations as to the condi- 

 tions under which illuminants of this class are to be used and 

 stored are absolutely necessary. 



The advantages in point of convenience and efficiency which 

 attend the employment of electric glow-lamps for illuminating 

 the pit's bottom and roadways immediately adjacent to it have 

 already been demonstrated at several collieries where this utilisa- 

 tion of the electric light has been combined with illumination at 

 the surface by arc lights. In applying electric glow-lamps to- 

 underground illumination, to the extent indicated, through the 

 medium of conducting caljles leading from the generators to the 

 pit bottom, it is essential to safety, as well as to the permanent 

 efficiency of the installation, that the cables should be placed in 

 positions where they are thoroughly protected against possible 

 accidental injury. It is also essential, in all mines where fire- 

 damp has been known to occur, that the glow-lamps should be 

 excluded from direct contact with the air of the mine in one or 

 other of the ways indicated in this report. Portable, self-con- 

 tained electric lamps have been devised which will furnish for 

 several successive hours a light considerably superior to that of 

 the best safety-lamps, and which at the expiration of eight hours 

 and upwards will still give a light fully equal to that of a 

 freshly lighted Davy lamp. These lamps are perfectly safe, but 

 as they do not afford any indication of the condition of the 

 atmosphere in a mine, their employment, even if special fire- 

 damp detectors are used, cannot in any case entirely dispense 

 with the necessity for the use of some safety-lamps. For 

 exploring purposes after accidents, or in foul places, these la tips 

 must prove very valuable even in the present condition of their 

 development, and as auxiliary lights they cannot fail to prove 

 very useful. The great progres-i which has recently been made 

 in the construction of portable electric lamps affords promise of 

 a speedy utilisation of such lamps to an important extent in coal- 

 mines. 



While we think that the safety-hooks at present available 

 may have contributed to prevent fatalities from over-wind- 

 ing, we believe that the best appliance for the purpose is an 

 automatic steam brake attached to the winding-gear, and we 

 think it desirable that such brake should be introduced where 

 practicable. 



We consider that measures should be adopted to deal more 

 systematically, and if possible more expeditiously, with casualties 

 resulting from the various sources of accidents dealt with in this 

 report. Collieries or mines should be required to provide an 

 ambulance and stretchers for the purpose of conveying to their 

 homes suffijrers from injuries received w^hile in the discharge of 

 their duties. Arrangements should be made for the establish- 

 ment of centres in mining districts, where additional appliances 

 for succour and relief, and also special appliances for exploring 

 purposes, should be maintained in an efficient condition, so as to 

 be ready for use at the shortest notice. It is most desirable that 

 facilities should be afforded for the instruction of men in the use 

 of special auxiliary appliances for exploring purposes, and in 

 simple measures connected with the provisional treatment of 

 injuries. We attach great importance to the systematic inspec- 

 tion of each mine by the workmen, as provided for in General 

 Rule 30 of the Coal Mines Regulation Act, 1872, and we re- 

 commend that this provision should be generally and regularly 

 acted upon. 



Concludiug Obscfvations 



In submitting to your Majesty the results of our inquiries and 

 experimental work, and the conclusions to which they have 

 led us, we desire to express our regret at the unavoidable delay 

 which has occurred in the presentation of our report. This 

 delay has been due to the wide range of important and veiy ex- 

 tensive subjects included in the reference to us, and to the great 

 difficulties we have experienced in bringing to a close the experi- 

 mental work upon which we have been engaged, almost con- 

 tinuously, since we first entered upon the inquiiy intrusted to 

 us. These difficulties have arisen in part out of the constant 

 succession of inventions and suggestions submitted to us in 

 connection with the questions under investigation, many of 

 which demanded careful consideration and necessitated the insti- 

 tution of fresh experiments. They have also been in part due 

 to the circumstance that, as our investigations progressed, the 

 results obtained opened up new fields into which it was necessaiy 



