352 SCIENTIFIC NOTES. 



of the Ironmongers' Company, we should suppose that, having decided 

 to abolish the habit of high feeding, these teeth were prominently brought 

 forward to prove that, for the future, the masticatory organs of the members 



would 



" Hang 

 Quite out of fashion, like a rusty mail, 

 In monumental mockery." — Troilus and Cressida. 



SCIENTIFIC NOTES. 



New Use of Bark — Cheap Blasting-Powder. — A patent has been taken 

 out in Belgium for a simple method of making blasting-powder from spent 

 tan bark. It is said that while the price of this powder is less than that of 

 gunpowder, it takes but one-seventeenth part as much to produce the same 

 effect. It is composed of 52J lb. of waste tan bark, and 20 lb. of pulverised 

 sulphur. The nitrate of soda is dissolved in a sufficient quantity of boiling 

 water, and the tan bark added in a manner to completely impregnate it 

 with the solution, after which the sulphur is added in the same way. The 

 mixture is taken from the fire and thoroughly dried, when it is ready for 

 use. If it is wet, it does not permanently injure it, but on being dried 

 again is as good as ever. If fired in the open air, it causes no explosion, 

 but is very efficient for blasting when confined in the usual manner. It is 

 not suitable for use in guns or cannon. 



A New Canadian Dye. — Professor Lawson exhibited specimens of a 

 dye of great richness, prepared in the laboratory of Queen's College, 

 Kingston (Canada), from an insect, a species of Coccus, found for the first 

 time last summer on a tree of the common black spruce (Abies nigra, 

 Poir.) in the neighbourhood of Kingston. This new dye closely resembles 

 true cochineal, a most expensive colouring matter, capable of being pro- 

 duced in warm countries only, and which is used to give a fine and 

 permanent dye, in red, crimson, and scarlets, to wool and silk. Unlike 

 cochineal, the new dye discovered at Kingston is a native Canadian pro- 

 duct, capable of being produced in temperate countries, having been but 

 recently observed. A sufficient quantity has not yet been obtained for a 

 complete series of experiments as to its nature and uses ; but the habits 

 of the insect, as well as the properties of the dye, seem to indicate that 

 it may become of practical importance. In colour it closely resembles 

 ordinary cochineal, having rather more the scarlet hue of the flowers of 

 Adonis autumn alis ; and, no doubt, other shades will be obtained. The 

 true Mexican cochineal is now being cultivated in Teneriffe, and other 

 vine-growing countries of Europe and Africa, with such success as to 

 displace the culture of the grape-vine ; yet the Directors of the East 

 India Company offered in vain 2,000J. for its introduction into India, — 

 Proceedings of Botanical Society of Canada. 



