and of ventilating Coal Works. 101 



Dalkeith, Mkllothian, Scotland) wherein " the money pro- 

 duce per acre from the same Seams, had nearly been doubled, 

 by the change to the Derbyshire or long-way of working :" it 

 would seem, however, from your Alnwick Correspondent's 

 statement in p. 30, that little success has yet attended the 

 recommendation. 



Now, perhaps, when the rage for " Safety-Lamps," as the 

 means of bolstering-up the vicious system of working, against 

 which I have often addressed your Readers, and those of some 

 other periodical Works, has had time to subside ; when a be- 

 ginning has been made, as mentioned in p. 31, and your zea- 

 lous Correspondent has, upon the spot, undertaken to advo- 

 cate and enforce the matter, I begin to have some hopes of 

 seeing a change gradually effected. In the mean time, I should 

 feel much obliged, by seeing the following particulars or any 

 of them stated in your pages ; viz. what are the dimensions of 

 the Measure, which your Correspondent calls a Boll P and 

 whether it is heaped? How many pounds does a Boll of 

 Coals weigh ?, in average and in extreme cases. How many 

 superficial square yards constitute the Darg ? which he men- 

 tions: probably theDaiigh, of the 2nd Report on Weights and 

 Measures, September 1820, means the same thing?; but it is 

 there spoken of, as an uncertain Scotch Measure of Land. 



The Names and Situations, and as many particulars as he 

 can and may be willing to furnish, of the Collieries, in or near 

 to Northumberland, where the " way-going" method may 

 have come into use?; explaining, if he can, which are their 

 several Seams (like Cuper's-eye, Belford and Bulman Mains) 

 with reference to the numbered Strata, in the " Section of the 

 Strata," lately published by Mr. Westgarth Forster ?. 



I must agree with your Correspondent in thinking, that 

 mechanical means are inadequate, to the effectual ventilation 

 of large Coal- Works on the " Pillar " plan, and that where 

 the Derbyshire or " long-way " is adopted, such means are 

 rarely wanted, and only for temporary purposes, whilst pre- 

 paring or fitting the Woi'ks ; when the simple " Ventilator," 

 which Mr. John Taylor has described to the "Society of Arts," 

 (see their 28th volume, p. 219) might occasionally be very 

 useful. 



I am yours, &c. 

 Howland-strcet, Feb. 5, 1823. JoHN FaiiEY. 



XXIV. On 



