236 Intelligence and Miscellaneous Articles, - 



liquid. And when we further consider that her surface undergoes 

 for a fortnight at a time the uninterrupted blaze of the sun unmodi- 

 fied by air or vapour, we feel pretty certain that if her surface were 

 covered with ice, a large portion of it would be turned into vapour 

 long before the fortnight was over. What would become of a lump 

 of solid oxygen under the same treatment we do not know. 



It is much to be regretted that Mr. Proctor should have disfigured 

 a very meritorious book by these crude speculations. We trust that 

 a second edition will be soon called for, and that he will take that 

 opportunity of correcting his errors by means of a little judicious 

 omission. 



XXXI. Intelliqence and Miscellaneous Articles. 



RESULTS OF BLASTING-EXPERIMENTS MADE WITH NITROGLYCE- 

 RINE AT VIEILLE-MONTAGNE MINE. NOTE BY M. NABEL. 



HPHE greatest advantage of nitroglycerine consists in the fact that 

 when it is used a force can be introduced into the blast-hole of a 

 mine ten times as great as when powder is used. Hence arises a great 

 economy in manual labour, the importance of which is understood 

 when it is remembered that the labour of the miner represents, 

 according to the hardness of the rock, from five to twenty times the 

 value of the powder required — a saving therefore which will often 

 amount to 50 per cent. 



The use of this substance is very simple. If the blast-hole of the 

 mine is fissured, it must be lined with clay in order to render it 

 tight. Nitroglycerine is then poured in, and the upper part of the 

 hole is filled with water ; in the nitroglycerine is then introduced a 

 safety-match of suitable length, at the end of which is pressed a 

 strong percussion-cap. The operation is finished, and it is only 

 necessary to put fire to the match. Sand may also be used to close 

 the hole of the mine above the charge ; but the operation is then a 

 little more complicated. In all cases ramming is useless. 



The following are the results of three experiments made with 

 nitroglycerine in the open works at the mine of Altenberg in the pre- 

 sence of M. von Decken, M. Noeggerath, and several German and 

 Belgian mining engineers. 



The rock in which the blast-holes were placed is stratified do- 

 lomite, a stratum internally hard and sound, but traversed by nume- 

 rous fissures, and merely superficially decomposed at the points of 

 contact with the stratification. 



First experiment. — A blast-hole of Jths of an inch (34 millimetres) 

 was bored perpendicularly in a dolomite rock, forming one of the 

 sides (60 feet in length) of an excavation (crater-shaped) of 17 feet 

 in depth. The hole was placed at a distance of 14 feet from the edge 

 of the almost vertical side of the rock. At 8 feet deep it would have 

 traversed a fault filled with clay about 1J feet deep. To prevent the 

 injurious effect, of this fault, the hole was only bored to 7 feet in 



