MKC1IANICS AND USEFUL ARTS. Ill 



in musketry had been proved by English made gun-cotton in English 

 rilies by an English general, to perform all that had been reported 

 concerning the Austrian gun-cotton. 



The next application of gun-cotton made during the past year was 

 to the driving of tunnels, shafts, and drifts in connection with engi- 

 neering work. It had been stated by the Committee that J- of the 



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weight of charge of cotton was equal in blasting effect to gunpowder, 

 and this had been proved in practice in a number of instances. At 

 Wingerworth colliery, in driving a shaft through soft but solid rock, 

 -g of the weight of gun-cotton as compared to gunpowder, and 

 in the slate quarries at Llamberis, at Allan Heads, ^ were re- 

 quired. At Allan Heads, in some lead mines, a tunnel was be- 

 ing driven seven miles long. The drift was seven feet bv iive in 



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the hardest limestone. Both ends were worked with gun-cotton fired 

 by an electric battery. The great advantage experienced was that the 

 air was not contaminated by smoke, and that the work could be carried 

 on more rapidly. The next application of it had been to the detach- 

 ing of large masses of rock. This had been tried in several places, 

 and it was found that one pound of gun-cotton was able to detach from 

 30 to GO tons of rock. 



Mr. F. A. Abel added some remarks on the chemical condition and 

 manufacture of gun-cotton. He stated that the manufacture of it was 

 much safer and more uniform than that of gunpowder, and when made 

 its stability is permanent and could be relied on. He believed the 

 Report of the French chemists against its permanency was founded on 

 experiments made with imperfectly manufactured material. Working 

 with large quantities during the last twelve months, he was satisfied it 

 did possess permanence, though he stated that under certain conditions 

 of packing and exposure to too high a temperature a slight change 

 did take place ; this he believed arose from some foreign ingredients 

 in the cotton. 





