MEANS OF PREVENTING COAL MINE EXPLOSIONS. 153 
system of doing nothing—was anxious to bleed, to purse, to blister, etc. Now the 
difference of opinion in this case was not due to scepticism; but on the one side to 
justifiable faith, that is, faith justified by knowledge; aud, on the other, to absence of 
that knowledge. The case was one of degenerative change—retrograde metamorphosis 
—of arteries. One had become so rotten that its wall had given way, its contents had 
escaped, a clot had formed, and by its mechanical effects given rise to the symptoms. 
The heart shared in the degenerative changes. The bleeding had ceased. To those who 
undeistood the real nature of the case, the lesions present, and the mode in which they 
had been produced, in short, the pathology of the case, belief in the efficacy of so-called 
active treatment appeared to be not only unjustifiable faith, foundationless faith, faith 
without knowledge, but to be faith in opposition to knowledge,—which in medicine is 
the worst form of scepticism, inasmuch as it implies doubt of truth, and a belief in error 
—doubt which might prevent the saving of life—a belief which, embodied in practice, 
might kill .—The Lancet. 
MEANS OF PREVENTING COAL MINE EXPLOSIONS. 
Mr. Bessemer, in a communication to the ‘ Times,’August 11th, on this subject, 
states that he is now engaged in investigating the action of combustion under excessive 
pressure in furnaces where the flame is bottled up like steam in a steam-boiler, by which 
means the heat is intensified in the ratio of the pressure employed. In one modifica¬ 
tion of these furnaces the workmen operate in a large iron room, where the pressure of 
the atmosphere is greater than it would be at a depth of ten miles below the surface of 
the earth, and when the temperature, under ordinary circumstances, would be such that 
no one could endure it for an hour. These furnaces, by a simple arrangement, may be 
supplied with thousands of cubic feet of air per minute, as cool as or cooler than the 
surrounding atmosphere. 
Mr. Bessemer proposes to apply this principle to coalmines. He observes, “The 
miner, enclosed all day between black masses of coal above and around him, requires a 
powerful light to see what he is doing—a light that never fails, that never goes out, 
that never requires trimming, and, above all, a light that effectually prevents the mix¬ 
ture of air and gas which pervades all coal mines from entering the flame and becoming 
ignited. Now, these are precisely the conditions obtained by combustion under pressure, 
which offers to the miner a source of the most brilliant light wholly inaccessible to the 
inflammable air of the mine. As a simple illustration of the fact, let us suppose a 
small iron box, a little larger than a policeman’s lantern, having a thick plate srlass, or 
a bull’s-eye, on one side of it; in the lower part is a common gas-burner, supplied by 
a pipe from a gasometer above ground ; the supply of air to support combustion is 
arranged in a similar manner, and supplied under pressure from aboveground ; a small 
aperture is made in the top of the lantern for the escape of the products of combustion. 
Now, if the air and gas are supplied to this light under a pressure of, say, 1 lb. per 
square inch, the light would be brilliant, and the escape from the orifice at this pressure 
(or even far less) would prevent the possibility of any external gases entering and be¬ 
coming ignited. In this way every gallery in a mine may be lighted like a workshop, 
to the great comfort and cheerfulness of those whose whole lives are spent in the cheer¬ 
less gloom of -these dangerous workings.” 
In reference to the above proposal, Mr. David C. M‘Vail, house surgeon to the Alnwick 
Infirmary, states that more than a year ago an article in the ‘ Lancet ’ drew r his atten¬ 
tion to the subject, and he then proposed a method which he thinks superior to that 
described above. His plan was to illuminate mines with hermetically sealed lamps, to 
which fresh air might be brought by tubing, either from above ground or from some 
safe part of the main gallery, the spent air being carried away in the same manner. 
The experiments had been tried several months ago with a hermetically sealed lamp, in 
which coal gas was kept burning, to reach which the fresh air had to pass through a 
tube 110 feet in length and of half inch bore, and to leave which the spent air had to 
pass through a tube of similar bore and 50 feet long,—the air was forced in by means 
of common bellows. Mr. M‘Vail thinks that this mode of lighting mines has the 
following advantages :— . 
