130 Chronicles of Science. [Jan., 



important properties of this new powder is that it does not require 

 to be heated in cold weather, whilst it is necessary first to heat 

 nitro-glycerine and dynamite, which operation has caused many 

 accidents. According to the information we have received, the 

 " poudre d'ammoniaque " was invented by Xorbin, the chemist. 

 The l Journal of German Public Works ' contains extracts from the 

 report of the Prussian architect, Steenke, amongst which are the 

 following remarks concerning poudre d'ammoniaque : — " Experi- 

 ments have been made by attaching a lamp to a 'pendulum, and 

 causing it to oscillate. Powder, gun-cotton, nitro-glycerine, and 

 dynamite ignited the moment the flame passed beneath them, but 

 poudre d'ammoniaque only commenced to burn when the flame had 

 touched it twenty times. 



u Making experiments to ascertain the pressure requisite to 

 explode it, it was found that, with the instrument employed, 

 explosion followed when the weight descended from 4 • 5 ft. to 5 • 5 ft. 

 with powder, 1 • 6 ft. to 2 • 25 ft. with nitro-glycerine, 3 ft. to 3 • 3 ft. 

 with dynamite, and from 13*125 ft. to 14 "2 ft. with poudre 

 d'ammoniaque." 



The production of gold in Australasia, according to the quarterly 

 returns issued by Mr. K. Brough Smyth for Victoria, and the re- 

 ports from other quarters, continues to be almost as large as ever. 



The quantity of gold exported from Victoria to the 10th of 

 September was 1,145,170 ounces, of which 154,075 ounces were 

 from New Zealand. Very remarkable things are said of the gold 

 fields of the latter place. Some of the quartz, broken from the 

 reefs, or veins, have yielded in recent crushings 30 per cent, of 

 gold. Mr. E. Brough Smyth's book on gold mining will be noticed 

 hereafter. 



The want of scientific knowledge amongst our miners is shown 

 in a curious way by some statements which have lately appeared 

 in * The Mining Journal ' on " The Prosperity of Mexico." The 

 "Correspondent" informs us that some curious stones have been 

 discovered at Tula del Hidalgo, " which present a great variety of 

 appearances, and each face has received, and is constantly receiving, 

 the landscape in front of it, by means of a colour so perfect, that 

 I believe that art itself cannot produce such relative exactness/' 

 Again, we are told, " The faces which begin to receive the first 

 impressions only present the images of the nearest trees with a 

 wonderful perfection and beauty; those that have been in one 

 position for a long time without variation present the complete 

 landscape within the visible horizon, and even the most distant 

 mountains by which it is limited." We perceive in this description 

 a great want of the habit of observation, and a considerable display 

 of " Our Correspondent's " fancy. It will be evident to every one, 

 possessing the slightest knowledge of Mineralogy, that the stones 



