September 2, 1915] 



NATURE 



25 



MINERAL INDUSTRY OF CANADA. 

 'yHE Canadian Department of Mines has issued, 

 A almost simultaneously, the annual report on the 

 mineral production of Canada during the calendar year 

 1913 and the^ preliminary report on the mineral pro- 

 duction of Canada during the calendar year 1914. 

 Neither of these reports presents any feature .of out- 

 standing interest, except that the effect of the war 

 upon the mineral industry of Canada is here made 

 evident. The value of the output in 1913 showed an 

 increase of 784 per cent, upon that of the previous 

 year, whilst that for 1914 shows a decrease of ii-8 per 

 cent, from that of 1913. It is, of course, not abso- 

 lutely clear that the decrease is wholly due to the war. 

 For example, the silver production of Canada, which 

 showed a slight decrease already in the former year, 

 has fallen about 16 per cent, in the latter year; the 

 silver production is due in very great measure to the 

 output of the Cobalt district, Ontario; in 1904, when 

 the production of this district commenced, the annual 

 production of silver was 3^ million ounces, whereas 

 in 1910, when it reached its maximum, it was nearly 

 thirty-three million ounces, and silver ranks second in 

 total value only to coal amongst the mineral products 

 of Canada, having amounted to 14-4 per cent, of that 

 total in 1913. Both the amount of silver and the 

 grade of the ore got in the Cobalt district have shown 

 a gradual decline of recent years, and there appear to 

 be some reasons to suppose that the life of the mines 

 in this district is not likely to be a long one. A de- 

 crease in silver production' might therefore have been 

 expected normally, and it is quite possible that the 

 part played by the European war in the recorded 

 decrease is not an important one. Other decreases, 

 such as those in coal, pig-iron, cement, and clav 

 products, are, on the other hand, to be referred in all 

 probability entirely to the war crisis. The three 

 former showed substantial increases in 1913 over the 

 previous year, and although the clay products fell off 

 in value in that year, this was due' merely to a tem- 

 porarily decreased demand for brick, owing to the un- 

 favourable financial position, which seriouslv limited 

 building operations in the Dominion. A careful study 

 of the two reports indicates no ground for supposing 

 that the mineral industry of Canada is in other than 

 a thoroughly sound condition, or that its expansion in 

 the future will be unable to keep pace with any de- 

 mands that may be made upon it. 



EXPLOSIVES. 

 'yHE Smithsonian Institution, Washington, has 



-'■ recently issued an article bv Major Edward P. 

 O'Hern, of the Ordnance Department, U.S. Army, 

 which deals with the composition, methods of employ- 

 ment, and results obtained with explosives. 



The author divides explosives into three classes : 

 progressive or propelling explosives, known as low 

 explosives; detonating explosives or high explosives; 

 and detonators or fulminates. For all classes the 

 effect of the explosion is dependent upon the quantitv 

 of gas and heat developed per unit of weight and 

 volume of the explosive, the rapidity of the reaction, 

 and the character of the confinement, if anv, given 

 the explosive charge. The rapidity of reaction varies 

 greatly with different explosive substances and with 

 the manner in which the explosion is started. 



Black gunpowder, smokeless powder, and black 

 blasting powders are known as low explosives, for 

 certain of which, such as smokeless powder, the ex- 

 plosion does not differ in principle from the burning 

 of a piece of wood or other combustible. The com- 

 bustion is very rapid, but is a surface action pro- 

 ceeding from layer to layer until the grain is 

 KO. 2392, VOL. 96] 



consumed. Such materials are known as low or pro- 

 gressive explosives, although the total power developed 

 through the combustion of a unit weight may be very 

 great, and would be destructive unless properly con- 

 trolled. 



In high explosives, such as dynamite, nitro- 

 glycerin, gun-cotton, some blasting powders, and 

 most of the "permissible explosives" approved by the 

 U.S. Bureau of Mines for use in mines where gas 

 explosions are liable to occur, the progress of the 

 explosive reaction is not by burning from layer to 

 layer, but the breaking up of the initial molecules 

 gives rise to an explosive wave which is transmitted 

 with great velocity in all directions throughout the 

 mass, and causes its almost instantaneous conversion 

 into gas. The velocity of propagation of the deton- 

 ating wave has been determined for some materials 

 to be more than 20,000 ft. per second, or approxi- 

 mately four miles per second; this form of material 

 is used in shells and for bursting purposes. The 

 progressive emission of a gas from a low explosive, 

 such as burning gunpowder, produces a pushing effect 

 upon a projectile, whereas the sudden conversion of 

 an equal weight of material into gas, as would happen 

 with a high explosive such as dynamite or nitro- 

 glycerin, would develop such high pressure and shat- 

 tering effect as to rupture the gun. 



The action of fulminates is much more brusque and 

 powerful than that of the high explosives. Since they 

 can be detonated by shock or the application of heat, 

 they are used in primers and fuses to start action in 

 both low and high explosives. The most important 

 is fulminate of mercury, which produces a pressure 

 of about 48,000 atmospheres. 



At no time In the history of the world have explo- 

 sives played such an important part In deciding the 

 destiny of nations as they are playing to-day In the 

 prosecution of the present war. Their extensive 

 use in the mighty engines of destruction, such as the 

 submarine mine, the torpedo, and In projectiles thrown 

 from cannon to great distances with marvellous 

 accuracy, is resulting in loss of life and destruction of 

 property on an unprecedented scale. 



Beginning with black powder, the earliest record 

 of which In actual war was in the fourteenth century, 

 the author follows the development of powder through 

 Its early stages of brown powder to the two principal 

 forms of smokeless powder for military purposes — 

 nitro-cellulose and nitro-glycerin — stating that the use 

 Is quite evenly divided; the U.S. Army and Navy, the 

 French Army and Navy, and the Germany Army using 

 the former, and the British Army and Navy and the 

 German Navy using the latter. He then gives much 

 detailed Information concerning the manufacture, life, 

 source of supply, and tests of smokeless powder manu- 

 factured from nitro-cellulose or gun-cotton. Follow- 

 ing which, subjects relating to life of guns, bursting 

 charges for projectiles, armour-piercing projectiles, 

 high explosive shells, shrapnel, fuses, aeroplane bombs, 

 means of Igniting explosives, mines, torpedoes, and 

 the storage and shipment of explosives In the United 

 States are discussed. 



THE BONAPARTE FUND FOR THE 



YEAR 1915. 



nPHE committee appointed to consider the requests 



■■• for assistance from this fund have examined 



twenty applications, and made the following proposals, 



which were accepted by the Academy ; — 



3000 francs to Auguste Lameere, professor at the 

 University of Brussels, to assist him to continue his 

 researches at the zoological station of Roscoff, 

 4000 francs' to M. Le Morvan, assistant astronomer 



