USEFUL PROJECTS. 



867 



Simple Means of correctirigthe Damp 

 in Coal-mines. \_Fromthe Month- 

 hj Magazine.'} 



Sir; 

 I have frequently noticed that 

 coal-works in Wales are interrupt- 

 ed by what the colliers term the 

 damp, but which is nothing else 

 than an excess of hydrogen gas. 

 This circumstance is often afflicting 

 to humanity; for it is not unusual 

 for the gas to take fire from the 

 lighted candles attempted to be in- 

 troduced into the work; the damp 

 on such occasions, burns withablue 

 flame: explosions* ensue, and very 

 often the miners in the work, and 

 the winders at the mouth of the pit, 

 fall victims to this inevitable catas- 

 trophe. The coal-mines belonging 

 to lord Cawdor, at Lanlash, in Car- 

 marthenshire, were, about a month 

 past, annoyed with this damp, which 

 rendered the miners heavy and 

 sleepy, and made it impossible for 

 them to keep in their lights. Being 

 informed of the circumstance by 

 William Dafydd, of Tuyha, the 

 present overseer of the works, I 

 requested him to slacken a few 

 lumps of fresh lime in the level, or 

 subterraneous passage made by the 

 miners in digging out the coals, 

 having an idea that the carbonic 

 acid gas, produced by throwing a 

 few lumps of lime into a little wa- 

 ter, would correct the air in the 



works, and make it more favour- 

 able to inhalation and combustion. 

 The overseer complied with my 

 request, and sent me word next 

 day, that the experiment was at- 

 tended with success, and the mi- 

 ners enabled to go on with the 

 works. The prevalence of the 

 damp in coal-mines is so general, 

 and its effects so dangerous, by 

 privation of lives, that I conceived 

 this success in applying a cheap and 

 rational remedy should be known 

 to the public ; that knowledge can- 

 not be better promulgated, than 

 through the medium of your exten- 

 sively-circulated, and most useful 

 publication. Yours, &c. 



John Jones. 

 Holborn-court, Gray's-inn. 



On the Propriety of establishing 

 Parochial Shops in Country 

 Districts. [^From the Universal 

 Magazine for Aug. 1809.] 



SiR;_ 



As the internal economy of la- 

 bouring parishes cannot fail to be 

 an object of general interest, per- 

 mit me to mention one particular, 

 in which, it appears, a consider- 

 able improvement might be intro- 

 duced to rural districts. 



Those who are in habits of fa- 

 miliarity with recluse parts of the 

 country must be aware of the very 



great 



• The writer rather questions the propriety of the term explosion, or loud ex- 

 plosion, as the lectures on chemijitry denominate the sound caused by the combus- 

 tion of a combination of gases; he has sometimes set on fire, in a quart bottle, with 

 a little water at the bottom to protect his hand, a mixture of hydrogen and oxygen 

 gases, and to determine whether the sound was from explosion or from inpletion, 

 has placed a small cork in the neck of the bottle ; on every occasion, the cork has 

 been driven in with violence into the bottle; he must therefore submit the cir- 

 cumstance to professed chemists ; and, more particularly, as his present laborious 

 profession is as distant from the subject as lavr is from physics. 



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