[ 577 } 



XXVIIl. Analysis of the Molra Brine Spring near Ashhy -de-la- Zouche, Leicester- 

 shire ; with Researches on the Extraction of Bromine. By Andrew Ure, M.D. 

 F.R.S. 



Received June 5, — Read June 19, 1834. 



A HE Moira coal mines are intersected by so many faults and slips, that they afford 

 a very limited supply of water. The chief portion of the fresh water is drawn from 

 within three hundred feet of the surface, by a pump barrel of nine inches diameter 

 and six feet stroke, working' four or five hours a day. It is raised at the rate of about 

 seven strokes per minute, and amounts in this time to a volume of ninety-one gal- 

 Ions. There is a cistern at the bottom of the basset shaft connected with a reservoir 

 cut in coal, which holds four or five days' drainage of water. The engine is employed 

 in raising the fresh water not more than nine hours in a week. 



The shafts for working the coal vary in depth from seven to eleven hundred feet. 

 One shaft is 252 yards (or 7b6 feet) deep, and contains four lifts of pumps. The up- 

 permost of these pumps delivers the water, which is altogether saline, into a cistern 

 at the bottom of the basset shaft, whence it is raised from time to time. The average 

 quantity of salt water alone employs the engine about eighty minutes daily, or ten 

 hours in the week. The topmost lift of all the pumps delivers the water into a cistern 

 about ten yards down the shaft : if the water comes from the fresh reservoir, it is 

 allowed to run over at the top of the cistern down the drain into the brook ; if from 

 the salt reservoir, it is forced into the bath cistern by a forcing pump. The salt 

 water is pumped up at the rate of five strokes and a half per minute, constituting 

 seventy-one gallons per minute, whilst working, or about ninety hogsheads in a day. 



In working the main coal, a little salt water oozes out ; but this transudation, or 

 bleeding as it is called, ceases after a time. In some few places small dribblings 

 continue to issue, which collectively throughout the whole range of the Moira mines 

 do not, in the course of twenty-four hours, exceed fifty hogsheads, and are conducted 

 to the common reservoir. 



The transudation of salt water generally appears in any adit in the coal as soon as 

 driving commences. It slowly bleeds, but never spirts or springs forth as if from 

 pressure ; but its oozing is invariably accompanied with a faint hissing noise, as if 

 air were escaping at the same time. The liquid proceeds chiefly from small crevices 

 (pin-cracks), and seems associated with inflammable air, which separates as it trickles 

 down the face of the coal. The gas is occasionally abundant enough to admit of 

 being fired. In driving an adit in the solid coal to any distance, not so much as a 

 dram of water is found at any one point, and very little oozes from the roof or floor 



