14 
from a manufacture of snuff which was formerly carried 
on there, but the whole course of the stream abounds with | 
picturesque spots on which the eye and the pencil of the artist 
love to dwell. Its seclusion too, so near to the crowded 
outskirts of Bristol, comes with a certain surprise on the 
traveller over that smoke-begrimed district. 
Pursuing their way by the route already indicated, the party 
reached the “Speedwell Pits” which formed the ultimate bourne 
of their excursion. The splendid air-compressing machinery 
was first brought under their notice. This power is no new 
discovery. The compressibility of air was known as far back 
as the time of Crssrsius, a celebrated mechanician, who lived 
as far back as 250 years B.C.; its latest application on a grand 
scale was to the excavation of the Mont Cenis tunnel. It is 
believed that compressed air when it comes to be thoroughly 
understood and utilised, will do more for the miner than all 
the powers hitherto’ applied or invented. It will be the 
motor for doing all the hard manual labour ; it will supply the 
“life-giving element” pure air; it will drive the coal-cutting 
machine, and blast down the coal; it will strike and turn the 
rock-borer, and it will haul the debris away ; it will pump the 
water, and cool the mine; in short there seems no limit to its 
utility and adaptibility ; it may be said, indeed, to have solved 
the problem of deep mining. Hitherto the obstacle to mining 
at great depths has been the increase of temperature, which 
rises in proportion to the depth penetrated; and it is found 
that when the heat of the mine equals that of the human body, 
muscular power can no longer be effectively wielded. This 
difficulty is overcome by the propulsion of compressed air, which 
effectually reduces the temperature at the greatest depths. 
This was realised to-day by those—and they comprised the 
greater number of the excursionists—who descended the shaft, 
500 yards (more than a } of a mile) in depth, and then followed 
the gallery (nearly a mile in length underground) and found the 
air throughout pure and the temperature cool and equable. 
Having returned safely to bank, the party found at the 
residence of Mr. Hanne CossHam, within a hundred yards of 
