On the comparative Stiffness of Beams, 15 



coal lies more than a hundred fathoms from the surface, and in 

 it the excavations have been carried on for a considerable num- 

 ber of years, the pitmen being now employed in heaving away 

 the pillars left at the first working to support the roof. On the 

 morning of the 27th of June, the overman who first descended 

 the Isabella pit, finding the air in the mine to be impure, with 

 proper attention to the safety of the workmen about to follow 

 him, prevented them from going to work as usual, till the cause of 

 the obstruction had been ascertained and the ventilation restored 

 to its proper course. For this purpose the three Mr. Foggets 

 (resident viewers) with five overmen and three boys, ventured into 

 the mine, and soon discovered the stagnation of the atmosphere 

 to be occasioned by a body of water escaping from the five-quar- 

 ter seam, situated eight fathoms above the low main coal, forcing 

 away a large portion of roof, and bringing with it a quantity 

 of carburetted hydrogen gas. While taking measures to over- 

 come this accident, which had been long dreaded, the inflammable 

 air by degrees displaced the atmospheric air, and a blast was the 

 consequence, which in an instant destroyed all those who were 

 near it. 



Mr. G. Fogget, having been for some time in a bad state of 

 health, had quitted the parly before the fatal explosion; but ven- 

 turing back in hopes of saving his brothers and a son-in-law, 

 fell a victim to the azotic gas or after-damp with which the 

 mine was now filled. Nearly eleven hours afterwards a. boy 

 who accompanied him was found lying among the water and 

 mud in a state of insensibility, but, on the usual modes to restore 

 respiration being administered, slowly returned to life. 



Should the coal-owners of this district continue to pursue the 

 practice of obtaining the greatest quantity of coals with the 

 least possible expense, I fear you will have to record many more 

 of these horrid catastrophes. 



Nevvcfistle-upon-Tyne, -^^ 



July 6, 1815. 



VII. On the comparative Stiffness of Beams. 

 By A Correspondent. 



To Mr. Tillock. 



8iR,— JL HE most useful part of the theory of the resistance of 

 solids, is that which treats of the comparative stiffness of beams ; 

 yet in some of our best treatises on mechanics it is entirely 

 omitted ; and in others the calculations from theory are so 

 nnich at variance with the results obtained by experiment, as to 

 render them useless in practice. 



A piece 



