the Fire- and Chaah-Damps of Coal MiiiCd. 20,; 



•count of the extra oxvgea which it contains, is the best for 

 this purpose. 



** The utensils required for this business are small flat 

 stone dishes, made thick, about two inches deep ; and a 

 g'lass funnel for pouring in the acid of vitriol. The ingre- 

 dients are, common salt (it ought to be bay salt), oxide of 

 manganese, and concentrated acid of vitriol, which, iu 

 eonunon language, is the strongest oil of vitriol. 



Proportion Jar one Fumigation. 



oz. 



** Take of common bay salt - 3 



Fine powder of black manganese 

 Water _ - - - ] 



Strong sulphuric acid - - 1 



" After pounding the salt and manganese together, they 

 may be put into the stone ware dish, and the water poured 

 upon them; and afterwards the sulphuric acid, slowly,' 

 through a glasy funnel. This quantity is sullicient for a 

 s^ace of 16 feet by 12; but the frequent employment must 

 depend on the manner how ihe. fire-damp is evolved." 



To remove the choak-damp from coal mines the author 

 recommends the use of water. 



*■' Water, about the temperature of 40° of Fahrenheit, is 

 found to dissolve equal parts of its bulk ; but as the water 

 of a deep pit is commonly above 50°, it will take up two- 

 thirds of its hulk only. In order to effect this mixture with 

 water, T would recommend (savs the author) the common 

 ■fjre-engine, such as is used in the case of fire. The work- 

 men might for safety stand at a distance, and by directing 

 the mouth of the tube to the spot where the choak damp is 

 known to lie, the water mav be so diffused as to take up the 

 whole. The water will then taste acidulous, and lights will 

 burn, and animals breathe, in the place whence the vapour 

 was dislodged- That the diffusion of the water niight be 

 more speedy in dissolving the choak-damp, the tube might 

 be fitted after the manner of a garden walering-pol, so as 

 to sprinkle and break the fluid into a shower. 



" This kind of air being speedily attracted by quicklime, 

 by mixing that article in the water which is to be diflused 

 would still more effectually dislodge the choak-damp ; and 

 in places where it haj)pens to be collected in great (piantity, 

 juch a mixture would be highly servicciblc. 



" It ought to be remembered, whenever either /?;r-<fawp 



or choak-damp are detected in coal-pits, that there will b? 



fasou to f'Mr a collection of the other near the spot, if not 



K 4 powerfully 



