^56 



the stone loses nearly one half its weight. This carbonic 

 acid, which is in a gaseous state, is the same as what is 

 commonly called choke damp, and whose presence has so 

 often proved fatal to parties descending into pits or wells 

 that have not been properly ventilated. As an instance of 

 its injurious effects, I may here mention that at a colliery 

 in which I am engaged at Newton, near Castleford, where 

 our pit is sunk through a thick stratum of Limestone, we 

 have let the burning of Lime to a party who has now opened 

 an extensive quarry, and in the course of his workings has 

 excavated the stone within a few yards of some cottages. 

 He formed one of his kilns against the side of the rock, 

 (which is very open and full of seams,) next to the cottages, 

 and during the progress of the burning, the dispelled car- 

 bonic acid found its way through the crevices into the 

 cellar of the nearest cottage, which was excavated out of 

 the same stone. The consequence was, that the wife of 

 the inhabitant of the house, one morning, on descending 

 into the cellar, was seized with giddiness, and had great 

 difficulty in again ascending, when she fainted. Supposing 

 that this was merely an accidental attack, and before the 

 true cause was ascertained, a second and a third person 

 were similarly affected. The kiln which had caused this 

 catastrophe was afterwards speedily altered, so that the 

 heated mass of stone should not come in contact with the 

 face or side of the quarry, and all symptoms of choke 

 damp were then removed. 



Carbonate of Lime is found in many parts of England, 

 in large quantities, and in different states of purity. Geolo- 

 gically considered, it is discovered to exist, more or less, 

 in almost all the different strata of the Globe, whether 

 consisting of the primary, secondary, or tertiary rocks, 

 sometimes in seams of many yards in thickness, composed 

 of little else but the carbonate, and at other times forming 



