184 Prof. Bisehut" v/i the Inflammable Gases of 



sity up to the most powerful mixture for detonation, I have 

 tried the action of the safety-lamp, and convinced myself that 

 for the miner it is a real talisman. Extracts from my reports 

 on this subject will soon appear in Kars fen's Archiv. 



With the occiurence of inflammable pit-gases in Gerhard's 

 level you are acquainted from personal observation. It issues 

 from a Assure in the coal-formation sandstone, and burns with 

 a flame from 12 to 15 inches in height, and having a yellow co- 

 lour above, but a blue one below. As this gas does not exer- 

 cise the smallest pressure, or, in other words, flows out with 

 the pressm-e of the atmospheric air, I was obliged to adopt a 

 peculiar mode of collecting it. Tliis circmnstance likewise 

 proves that the fissures or the gas-canals have numerous ra- 

 mifications ; A\hen, therefore, the e^•olution of gas encounters 

 the slightest obstacle, it is immediately interrupted, and the 

 gas seeks another exit. The relatively higher temperature of 

 this gas is remarkable. You may well believe that I did not 

 neglect this subject : for the thermometer is, of a truth, a 

 most valuable instrument for assisting us to answer many geo- 

 logical questions. I found the temperature of the gas to be 

 10°.55 R. (55". 74 F.), while that of a bore 8 inches deep, in 

 the neighbouring rock, was lOM R. (54'.73 F.) Assuming 

 that the gas brings along Avith it the true temperature of the 

 place where it is formed, that the mean temperature of the 

 soil of the external crust of the eai'th at Saarbriick is 7^^.75 R. 

 (49 .44 F.), and that the increase of temperature towards the 

 interior of the globe is 1' R. (2°.25 F.) for every 115 feet ; 

 the gas must have come from a depth of 322 feet. The point 

 where the gas is evolved is 210 feet under the earth's surface, 

 so that, according to these data, the gas must have come from 

 a depth of 112 feet under the level. It may with probability 

 be assumed, that the gas is exposed during its progress to 

 cooling influences, inasmuch as it flows through colder strata, 

 and encounters colder waters. Its original temperature may, 

 therefore, be fairly estimated at more than 10\55R. (55^74 F.), 

 and must hence come from a greater depth. 



The inflammable pit-gas of the old level of IFcUesiceiler 

 jn'esents, in reference to its pressure, quite a difterent relatio . 

 The blower was cut out forty or fifty vears ago, and was fur- 



