432 PHILOSOPHICAL TEANSACTIONS. [aNNO 1773. 



the air's transparency ; and consequently the satellite, after having disappeared, might become visible 

 again, by a sudden increase ot the aii i transparency in tlie tract of the satellite's light, provided the 

 magnitude of the unshaded part remained, at the instant of the increased transparency, what it was 

 when the satellite first disappeared. But as this is not the case, as the unshaded part is continually 

 becoming less, the satellite cannot reappear, unless the increase of transparency be such, as to over- 

 balance the diminution of light made by the progress of the eclipse. And the motion into the shade is 

 so quick, that this can rarely, if ever, happen. By the like reasoning, fits of extinction are not to be 

 expected, when once the satellite has shown itself in an emersion. 



The author of these remarks does not imagine, that any apology is necessarj' for the liberty he has 

 taken. He has the highest opinion of the merit of Mr. Bailly's invention ; and this has excited him to 

 contribute what he could to obviate objections, and to prevent mistakes. 



XXVl. A short Account of an Explosion of Air, in a Coal-pit, at Middleton, 



near Leeds in Yorkshire. In a Letter from Mr. W. Barnard, of Deptford. 



p. 217. 



I have at length procured from my father, a memorandum made by him on 

 the spot, of the effects of foul air set on fire, which I have copied exactly as 

 below : 



" Being engaged in Middleton wood, the estate of Cha. Brandling, Esq. 

 near Leeds in Yorkshire, in directing the falling and barking of a large quantity 

 of timber bought of him in May 1758, I was witness of the following accident. 

 Some miners, being to renew their operations on the shaft of a coal-pit, which, 

 in a former year, had been sunk to the depth of 6o yards, in order to get through 

 a stratum of very hard stone, thought proper to drill holes, and fill them with 

 gunpowder. They afterwards from the top, threw down fire to blast the stone, 

 which made a report little louder than that of a pistol; but the blaze setting the 

 foul air on fire, produced an eflfect truly shocking. The whole wood was shaken, 

 the works at the mouth of the pit were all blown to pieces, and the explosion 

 was such as cannot be described. The vacuum in the air was so considerable, 

 that oak trees of a load or more each, at a great distance from the pit's mouth, 

 that before stood upright, stooped towards the pit very much, and must have 

 fallen wholly down, had not the air been instantly replaced. The bark-pullers, 

 at a quarter of a mile from the pit, were so alarmed by the shaking and explo- 

 sion, that not one of them would have remained in the wood, had they attempted 

 to blast it again, n. b. The trees in the whole circuit stooped towards the pit." 



XXVIL Extract of a Register of the Barometer, Thermometer, and Rain, at 

 Lyndon, Rutland, 1772. By T. Barker, Esq. p. 221. 



This is a register of the highest, lowest, and mean state, of the barometer 

 and thermometer, as also the quantity of rain, for each month of the year 1772. 

 The whole depth of rain for the year was 28^ inches. 



