684 Chronicles of Science. [Oct., 



the value of the lead being 1,448,9592., and of the silver 176,299?. 

 The production of Zinc is comparatively small, the total quantity for 

 1864 amounting to 15,047 tons only, whereas we imported 2,621 tons 

 of Zinc ore and 31,281 tons of Zinc, more or less pure. Our importa- 

 tions of iron pyrites was also much in excess of our production. We 

 need not detail the less valuable minerals ; suffice it to say, the total 

 value of the minerals obtained last year was 31,603,047/., the value of 

 the metals produced being 16,281,869/. 



A Swedish engineer, M. Nobell, has proposed the use of nitro- 

 glycerine instead of gunpowder for blasting purposes in mines. If 

 fired by the electric spark, or the gunpowder match, the explosive 

 force of this compound is considerable. In the course of the dis- 

 cussion in the Academy of Sciences of Paris on the use of this 

 nitro-glycerine, it came out that M. Ascagne Sobrero, a young 

 Italian chemist attached to the laboratory of M. Pelouze, treated in 

 1847 glycerine by a mixture of nitric and sulphuric acid, and ob- 

 tained a nitro-glycerine having the aspect of olive oil — yellow, 

 heavier than water, and insoluble in it, but soluble in alcohol and 

 ether, and which possessed all the properties of gun-cotton as an 

 explosive agent. The nitro-glycerine of M. Nobell is said not to 

 detonate at the temperature of 100° Cent., nor by the action of a 

 single spark. A commission, composed of MM. Eegnault, Pelouze, 

 Combes, Morin, and Chevreul, has been named to inquire into the 

 application of this fluid for blasting in mines.* 



Some experiments have been made in the tin mines of Altenburg, 

 in Saxony, which appear to have been very satisfactory. The great 

 advantages are the smallness of the holes required in the rock, and 

 consequently the great saving of the time in the miner. Gunpowder has, 

 it is stated, but one-tenth the strength of this liquid. The process of 

 blasting with the nitro-glycerine is very easy. If there are any fissures 

 in the rock, the hole or chamber must be first lined with clay, to 

 render it water-tight. This being done, the nitro-glycerine is poured 

 into the hole, a safety fuze, with a well-charged percussion cap, is 

 introduced into it, and the hole is filled with water, no other tamping 

 being necessary. Other experiments have been recently made in the 

 presence of a committee of the Royal Cornwall Polytechnic Society 

 in Cornwall, and the rending powers of this explosive compound has 

 been proved to be most remarkable. 



Shale Oil in New South Wales. — In the neighbourhood of Illawara 

 an inflammable substance has been long known to exist. Recent 

 examination has shown that this contains a large quantity of kerosene 

 oil. Some of this shale having been collected and carried to Sydney, 

 it was properly examined and found to be really of considerable value. 

 The quantity of oil yielded by twenty-one pounds of shale, when 

 subjected to distillation, was one gallon. It is stated that this oil can 

 be produced and packed in tins at Is. 6d. per gallon. 



* 'L'lnstitnt,' 10th July, 1865. No. 1646 . 



