Tonite is extensively used in torpedoes and for submarine blasting, also for quarries, &c. Large quantities were used in the construction of the Manchester Ship Canal. Among its advantages are, that the English railways will take tonite on the same footing as gunpowder; it is a very dense material; if wetted it can easily be dried in the sun; it very readily explodes by the use of a proper detonator; while it burns very slowly and without the least danger; the cartridges being waterproofed, it can be employed in wet bore holes, and it can be tamped with water; and finally, as it contains sufficient oxygen to oxidise the carbon, no carbonic oxide (CO) gas is formed, i.e., its detonation is perfect. It is a very safe explosive to use, being little susceptible to either blows or friction. Not long ago, a committee, composed of Prof. P. Bedson, Drs Drummond and Hume, Mr T. Bell, one of H.M. Inspectors of Coal Mines, and others, in considering the problem whether the fumes produced by the combustion of tonite were injurious to health, carried out a series of experiments in coal mines for this purpose. The air at the "intake" was analysed, also the air of the "return," and the smoky air in the vicinity of the shot holes. The cartridge was surrounded by the flame-extinguishing mixture, and packed in a brown paper bag. During the first experiment nineteen shots were fired (= 6.29 lbs. tonite). The "return" air showed only a trace of carbonic oxide gas (CO). At the second experiment thirteen shots were fired (= 4.40 lbs. tonite), and analysis of the air of the "return" showed that CO was present in traces only, whilst the fumes contained only 1.9 to 4.8 parts per 10,000. ~Dangers in connection with the Manufacture of Guncotton, &c.~--Of all the nitro compounds, the least dangerous to manufacture are gun-cotton and collodion-cotton. The fact that the Stowmarket Factory is within five minutes' walk of the town shows how safe the manufacture of this explosive is regarded. With the exception of the nitration and the compression into blocks or discs, the whole process is worked with a large excess of water, and the probability of an explosion is thus reduced to a minimum. Among the precautions that should, however, be taken, are--first, the careful extraction of the resinous and soluble substances from the cotton before nitration, as it was shown many years ago by Sir F.A. Abel that the instability of the gun-cotton first manufactured in England and Austria was chiefly due to these compounds. They are generally removed by boiling the cotton in a soda solution.