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To illustrate "An Investigation as to whether the Fumes produced from the use of Roburite and Tonite in Coal Mines, are injurious to Health."

from a species of blood poisoning, but this was not sufficient proof; he hoped Drs. Hume and Drummond would look into this, and perhaps be able to give the results of their further experience at another meeting. The reference to Tursdale (page 376) was not quite exact, the report stated that "owing to the condition of the district selected it was deemed desirable not to fire shots." As a matter of fact, the Committee were taken to a part of the mine which had not been worked for many years, and it was covered with dust, and so they decided not to fire a shot. He had gone into the question of the amount of ventilation in the Cleveland mines in comparison with the number of men employed, but he was afraid he could not sufficiently trust his memory to give the particulars now; it was, however, certainly stronger and greater than the amount per person employed in the Durham coal mines. At the time the Royal Commission was sitting, in 1864, there was no ventilation by machinery, and the mines were very smoky, the men complained, but without being able to prove very much. But now that they had mechanical ventilation there was no gas to do any harm.

Dr. P. PHILLIPS BEDSON said with regard to the President's question as to the proportion of carbon monoxide found in the return as compared with the place, he would point out that it was less at the return than at the place; one would naturally expect that to be so because it was diluted with the air, so much so perhaps that they might not be able to detect it. With regard to Mr. Cochrare's question, any explosive with which he was familiar would be injurious to a man working in an atmosphere overcharged with the fumes, just the same as in an overcrowded room, or a room overcharged with the products of combustion of coal gas; they all knew the effects of breathing bad air. The percentage present would depend on the amount of the explosive fired; if seven ounces of explosive were fired in 540 cubic feet of air the proportion of carbon monoxide would not be dangerous. The worst results they had obtained in the returns in these experiments were probably better than the state of the air in the gallery of an ordinary theatre. The question of handling these explosives was purely a physiological matter, and did not concern him as a chemist; the medical gentlemen had found no evidence of injury from handling, but probably enquiry as to this would be better made among the workpeople who were engaged in its manufacture, or in preparing the shots. If a man had a cut in his hand it might cause blood poisoning, but otherwise, he thought, there was no danger. Nitrobenzene had been and still was used for scenting soaps. It was possible to produce blood poisoning from gunpowder.

Mr. T. A. SOUTHERN (Derby) said carbon monoxide could not be breathed with impunity even when diluted with air, but the exact amount to produce a deleterious effect in respiration had, so far as he knew, not been determined.

Mr. A. SOPWITH said they would all agree that it was a most instructive and exhaustive enquiry; but he understood that they were indebted to the Durham Coal Owners' Association and Durham Miners' Association for the privilege of having the report read before the Institution and printed in the Transactions. He quite