328 Scientific Intelligence. [ApriL, 
the ventilation of mines, it is with great diffidence that I venture to 
lay before you the outlines of a plan that has for some time occupied 
my thoughts. Let series of tubes (Pl. LXV. Fig. 5), each extend- 
ing from one headway to another, and with one end shaped like a 
funnel, so as to receive the small end of the following tube, and 
at the same time admit a current of air from without, be fixed 
along the roofs of the different lateral workings, and all run into a 
miain tube that shall extend from the lowest dip to the upcast pit, 
and be there connected with a cylinder or pump wrought by some 
of the working gears. Here let one or more gasometers, similar to 
those for the gas-lights, be constructed, having a safety valve, con- 
nected with an upright or vertical tube, running up the shaft into 
open day. From these gasometers let a small tube be carried along 
one of the safe headways used by the miners down along the bottom, 
or its angle, where there is the best security from accidents. From 
this tube let small lateral tubes, either fixed or flexible, each fur- 
nished with a stop-cock, run off opposite to each place of work. 
Jets, with cocks, may also be fixed wherever they may be required. 
By now setting the pump a working the gasometers will fill with the 
carbureted hydrogen collected from the workings through which the 
lateral tubes extend, and then the gas acting on the safety valve 
will make its escape up the upright pipe to the surface, until the 
mine becomes clear from the gas, when there could be no risk in 
allowing flame to be applied to each of the jets and tubes, for the 
purpose of supplying the miners with abundance of cheerful light 
in their dreary abodes. Such, Sir, is an attempt to verify the pro- 
verb of turning our greatest bane to our greatest benefit, by con- 
verting the scenes of catastrophe, so prevalent of late, into scenes 
of illumination. Persons better acquainted with mines, and their 
localities, will no doubt be able to suggest many improvements. It 
may be objected that, though the pipes may succeed in clearing the 
workings from accumulated carbureted hydrogen, still danger may 
occur from blowers, or unforeseen vacuities, or wastes in the strata. 
To prevent this I would propose that a safety lantern be screwed upon 
each jet: and if any lantern proposed be thought too expensive, I 
will in my next propose a simpler and much cheaper plan of safety 
lantern. 
I remain, Sir, most respectfully, 
Your most obedient servant, | 
Hucu WALLACE. 
V. On Hannilal’s softening the Rocks of the Alps by Vinegar. 
By Col. Beautoy. 
Historians say that Hannibal by fire and vinegar softened the 
Alpine rocks, and made a passage for his army into Italy. May 
not this apparently strange assertion be thus explained :— 
By means of wood to make fires he supplied his pioneers who 
were cutting the road through the rocks with water, by melting the 
ice and snow, to satisfy the excessive thirst produced by the copious 
