LIVING UNDER WATER.

Tuapeka Times, Volume VI, Issue 326, 31 January 1874, Page 3

LIVING UNDER WATER.

{Froyn the " Bendigo Advertiser ;")

The escape of the miner John M'Cavi6ton from being drowned by the late, influx o£ water in the Hustlers' Reef Co.'.emine (a description of which appeared, in these columns) has given rise to, a considerable amount of controversy as to the possibility of compressed air confined in a drive by a superincumbent mass of water in a shaft being able to sustain life. The most opposite theories, home been advanced, and backed by •apparently unassailable argument, but still the fact remains that M'Caviston was imprisoned, for 27 hours at the end of a, 240 ft. drive, water at the same time standing in the shaft to the height of. between 50ft. and 60ft. abeve the level of the top of the drive. "Two descriptions of objections have been .raised -against the possibility of this

wcurrence— -one, that as the water descended the shaft it 'must have completely filled the drive ; and the other that admittin a certain quantity of air was imprisoned in the drive, it must have become so compressed as to be fatal to respiration. We take it there can be no denying the fact that M'Caviston was so imprisoned, and, this being allowed, it only remains to inquire into all the facts of the^cose, and ascertain, as far as practicable, underwhat circumstances he managed to exißt. It is useless again to enter into all the particulars of the accident, it being quite sufficient for our argument to consider that M'Cavißton had reached the end of the drive, behind which the roof rose lift, from the floor, and opened into a long chamber, crossing it at right angles. The length of this chamber is 80ft.; average height, 7f.; width, 7ft. The drive — as already stated, 140 ft. long — has a rise of 4ft. ; height, 6ft. 6iri. width, sft. Consequently, when the water rose in the shaft to the top of the mouth of the drive, there was a segment of air in the drive equal to at the base, 4ft. high by sft. wide, thining away to nothing at the mouth of the drive. In the chamber or cross-cut above referred to, there would be a stratum of air above the water level of 80ft. long, 4ft. 6in. high, and 7ft. wide. The water having reached the level of the top of the drive, it was not impossible for the confined air in the drive and chamber to escape ; and as the water rose in the shaft, so this air became more and more compressed towards the crosscut. When the water in the shaft was at the level of the top drive there was then confined air (not compressed) as follows :—ln: — In the drive, 1,400 cubic feet ; in crosscut, 2,520 cubic feet -, total, in round numbers, 4,900 cubic feefc. When the water rose to its highest level in the ahaf t the confined air waa then compressed (according to Boyle and Marriotte's law, the temperature remaining the same, the volume of a given quantity of gas varying inversely to the pressure which it bears) to a little less than onehalf or two-fifths of its original volume. The space thus occupied by the compressed air would be 1,568 ft., but of course there would be no diminution of tho quantity of oxygen, which gas is necessary to the support of life. The quantity of air necessary to the sustenance of life in one human beine is 266 ft., in 24 hour 3, and, as Mr. M'Caviston was confined only 27 hours in 1.569 ft., he had certaiuly enough and to spare. As to the contamination of this air by the evolution of carbonic acid gas from the lungs and body, this is estimated by competent authorities at 10 cubic feet in 24 hours. But no injurious effects are experienced by the breather until the mixtm-e of carbonic acid with the atmosphere assumes the proportion of 1 in 100, and, under the circumstances, it is more than probable, that the carbonic acid gas evolved by Mr. M'Caviston was for the most part absorbed by the great body of water, and the damp sides of the drive. The theory has also been advanced that the compression of the air would generate an extraordinary degree of heat, but this would rapidly be absorbed by the cold water that had fallen down tlie aL^, and tie wt eiica and roofof the space within which it was confined. M'Caviston, according to his own account, sat upon a heap of mullock at the end of the drive, with his feet hanging in the water, and, having been wet and wearied by previous exertions, naturally felt chilled. This would have been the case even supposing the heat of the compressed air had not been absorbed. With his feet hanging in cold water, boJy wearied, and circulation low, and evaporation from a constantly wet skin, the natural heat would very rapidly be abstracted from his body. The pressure of the atmosphere, equal to one and a-half added to the ordinary pressure, would not be at all likely to be felt by him. The sensation of pressure on tho body is felt in a greater degree in a rarefied atmosphere than in a denser one. A diver may sustain tho pressure of Beveral tons, of water on his body, but ho does not suffrr from it, because it 13 equal in every direction. A raasa of correspondence has reached us upon the subject of M'Cavieton's wonderful escnpe, and in the preceding remarks we have endeavoured to epitomise the various theories advanced, and to point out the. actual facts of the case, and the scientific deductions to be drawn from them. Accidents of the description which took place iv the Hustler's Reef Company have frequently occurred before, and wiil doubtless occur again, and it is a matter of the utmost importance Lhat in such emergencies miners should know in what direction Bafety lies.