103 CRITICAL NOTICES OF NEW PUBLICATIONS. 



Practical Observations on the Phenomena of Flame and Safetij 

 Lamps. By John Murray, P. S. A., F. L. S., &c. London ; 

 Renshaw. Second Edition. 1836. 



Wb received this interesting pamphlet, which abounds with use- 

 ful and practical information, at too late a period in the month to 

 allow time for more than a cursory glance at its contents ; but the 

 subject is of such vital importance to the thousands employed in the 

 mining districts by which we are surrounded, that we should consi- 

 der it a dereliction of duty to entirely omit a notice of Mr. Murray's 

 researches in the field of science. 



After an able dissertation on the beauty of the structure and 

 phenomena of flame, which the author clearly proves is not " solid,** 

 but " in texture a luminous bubble, inflated with inflammable va- 

 pour," he adverts to the colour and temperature of flame, and then 

 goes on to prove, most satisfactorily, the insecurity of Sir Hum- 

 phrey Davy's Safety Lamp when exposed to a current of air acting, 

 as it were, like a blow-pipe, and forcing the flame through the wire 

 gauze — an occurrence which must necessarily take place in travers- 

 ing what is technically called a blower, in the mine. This opinion 

 is completely corroborated by ]Mr. Gurney, in his evidence before 

 the select committee of the House of Commons, who stated, most 

 distinctly, that if hydrogen was mixed with the atmosphere. Sir H. 

 Davy's Lamp would not be safe under stationary circumstances ; 

 neither could it be relied on if moved at a rate of 300 feet per 

 minute in a carburetted hydrogen mixture. 



We will now proceed to quote Mr. Murray's observations and 

 description of the invention of Messrs. Upton and Roberts, of which 

 he speaks in terms of high commendation. 



" It seems to me obvious, after mature deliberation and reflection, that 

 Messrs. Upton and Roberts' Safety I^mp is the only one justly entitled 

 to the name ; nor can I conceive of any continffency in the mine that would 

 unhinge that claim and title, save the incidental fracture of the glass cylin- 

 der by external violence. I would, therefore, strongly recommend the sub- 

 stitution of a double envelope of Talc ; the amount of light would not 

 thereby be diminished, and the elasticity and flexibility of the material 

 would be ample guarantees for the preservation of its integrity. This Safety 

 Lamp has been exposed to the severest tests by Messrs. Pereira and Par- 

 tington, in the presence of competent judges ; and it must frankly be con- 

 fessed that the safety seems absolute^ nor is it easy to conceive of any combi- 

 nation of gases to be met with in mines that will disturb its pre-eminence. 



^ The invention of Messrs. Upton and Roberts may be briefly described 

 as consisting of a glass cylinder completely enveloping the wire cage of a 

 Davy Lamp. The air to supply the wick passes through apertures below 

 the cage; from these apertures the air is carried under two horizontal layers 

 of wire gauze, through which it has to pass through the wick ; these layers, 

 however, are entirely covered by a cone of metal which has an orifice about 

 the size of a sixpence in its centre, for the wick flame to pass through. This 

 contrivance, which produces the object sought for, namely, ' safety,' acts on 

 the principle of permitting none but the products of combustion to escape into 

 the Lamp — the gaseous products of flame, namely, carbonic acid gas, &c. with 

 the residual azote, are altogether negative with respect to flame ; and canse- 



