ON THE FIRE-DAMP OF COAL MINES. 149 



XI r. 



Experiments on the Fire-damp of Coal Mines, by William 

 Henry, M. D. ; including a Communication on the Sub- 

 ject from Thomas Thomson, M. D. F.R.S.E. Com- 

 municated by Dr. Henry, 



BOUT the close of 1S06, I received, from the Rev. History of the 

 William Turner of Newcastle on Tyne, two bladders filled ^ctedTexpt 

 with the fire-damp, which had been procured from a coal riment. 

 mine in the neighbourhood of that town. It was caught by 

 luting a common funnel over the month of a blower *, and 

 tying a compressed bladder to the pipe of the funnel, after 

 the gas had issued from it for some time. My experiments 

 were made on the gas, about seveu days after its being first 

 collected. At that time, the bladders were perfectly dry, and 

 bhowed no signs of putrefaction. 



The general results of these experiments (as stated in a General re- 

 memoir which was read in January 1807> before the Medi- 

 cal Society of Edinburgh) are the following. The gas was 

 found, by the test of nitric oxide, used in Mr. Dalton's me- 

 thod f, to contain about 4 its bulk of common air. It had 

 a disagreeable smell. When set on fire as it issued from the 

 orifice of a small pipe, it burned with a dark blue flame; 

 and a long conical glass vessel, held over the flame, was soon 

 bedewed with moisture. Mixed with common air, it did not 

 detonate on the approach of a lighted taper, at least in any 

 proportion that was tried. The utmost effect was a deep 

 blue flame, which spread quickly through the vessel, but 

 was not accompanied with any noise. With oxigen gas, 

 however, it exploded, and gave a loud report. On agitation 

 with limewater it lost about -V of its bulk. The nicest tests 

 did not discover any admixture of sulphuretted hidrogen. 

 One hundred parts by measure appeared, therefore, to con- 

 sist of 



* B'.o'.cers are holes or crevices in the coal or in the accompanying 

 strata, from which the tire-damp issues, sometime* with considerable 

 force. 



f Phil. Journ. XVI, 247; or I-tenry's Epitome, chap xii, v sect. 2. 



63*34 ' 



