8oMi; Rkcknt N'liows on' tiik .Siu.ikct ov JNIink Vi;NTrLATio\. GH" 



iKiufver, why allow tlieiii to be produced '. I can only unswci- this by 

 saying that I know of no way which will [trevent their production in 

 spite of the many patented mixtures which are alleged to do so. The 

 noxious gases to which 1 have referred are carbon monoxide and nitric 

 peroxide — the toxic effects of which, when present, even in very small 

 nuantities, are now so \evy well known. Dr. Haldane, indeed, has 

 made a special study of this subject for many years, and a large 

 amount of experimental work has been done by various scientific men 

 in Johannesburg. I can only call the effect of these ga.ses as deadly, 

 and it i'; they which cause that lamentable list of fatalities from 

 '•gassing." Their presence, or rather the presence of noxious gases, 

 has, liowe\er, always been recognised, and the mining regulations in 

 order to guard against accident contain a pro\ ision that miners must 

 not return to the face until a certain time has elapsed, during which 

 those gases are either allowed to diffuse, or are forced away through 

 the introduction of fresh air. In the experiments which I have carried 

 c>ut, but which are not 3'et complete, this regulation was purposely 

 neglected. The blasting was done as usual, but after the interval of a 

 Aery few minutes a man, who was provided with a safety helmet, i.e. a 

 helmet with the necessary appliances for furnishing him with a con- 

 stant supply of ox\'gen, went straight to the face and took samples of 

 the gases by means of the ordinary bellows which are used for sampling 

 flue and other gases, and these be blew into large glass bottles, which 

 were immediately thereafter closed with rubber stoppers. In order to 

 control results these were always taken in duplicate. Just in passing, 

 I may say that in any one of the experiments, if anything had gone 

 wrong with the oxygen supply, it would have meant certain death to 

 the man, or rather men, because for safety's sake another generally 

 accompanied him. Probably neither of them realised this. 



I pass now to a very brief resume of the results so far obtained, 

 but I may say in passing that the analysis of the gases presented a 

 great many difficulties, but these are being made the subject-matter of 

 a communication to another society. The method employed ultimately 

 was the so-called pentoxide of iodine one, which depends on the 

 principle that -when CO is passed o-ver 1,0-, heated to a certain tem- 

 perature, the CO is oxidised to CO.,, which can be estimated as such, 

 while free iodine is liberated and can be estimated by any of the ordi- 

 nary methods. 



The explosive used throughout was blasting gelatine, but occa- 

 sionally somewhat modified with the idea of producing during explo- 

 sion a larger proportion of oxygen than the ordinary variety. I may 

 also say that I selected what I thought would give both the best and 

 the worst results in practice. Several days sometimes elapsed before 

 the samples could be analysed, but in none of them could I detect 

 more than the merest trace of nitric peroxide, nitrous or nitric acids ; 

 and this is perhaps hardly to be wondered at, because the oxidation to 

 nitric acid would proceed very rapidly in the moist, hot atmosphere of 

 the mine, and as such Avould fall to the ground with the condensed 

 water. 



