PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 963 



l)loo(l-red color, a result from the formation of picramic acid. A 

 solution of cane sugar (sucrose), added to a solution of picric acid, 

 does not produce this change of color. 



A New Gunpowder. 

 Dr. Borlinetto has invented a new explosive compound, consist- 

 ing of 10 parts of nitrate of potash, 10 parts of picric acicl, and 8| 

 parts of bichromate of potash. The ingredients are to he sepa- 

 rately reduced to a fine powder, and then intimately mixed. 

 Some time since he proposed to use a mixture of chlorate of potash 

 and tannic or gallic acid. A compound almost identical with this 

 had been previously the subject of experiment, yet no practical 

 application of it is now made, owing to the uncontrollable violence 

 of the explosion. Ordinary gunpowder is not likely to be soon 

 superseded, on account of its comparative cheapness and the exten- 

 sive facilities for making it. 



EXTEACTION OF ArOMA. 



We lately gave the process for obtaining from flowers their 

 peculiar perfume by means of bisulphide of carbon. The light 

 product of crude petroleum has been found to be a capital substi- 

 tute for the bisulphide. This purified naptha readily takes up the 

 odor of flowers, which are continually added until the com]jound 

 is saturated, after which it is driven ofi:" by evaporation. The per- 

 fume may be separated from the oily matter associated with it by 

 means of pure alcohol, which. in small quantities does not unite the 

 latter. The aroma of several spices may be extracted in the same 

 way ; thus, too, may be secured the valuable medical properties 

 of a plant, particularly when they reside in its flowers. Care must 

 be taken to exclude the volatile naptha from the vicinity of fire. 



Surveying in Siberia. 

 The topographical corps of the Eussian Government has been 

 for some time employed in surveying the Kirghis Steppes, and the 

 vast tract of country lying between Si1)eria and China. They 

 have marked down the line of road by which the caravans travel 

 from the southern regions of Central Asia to the frontiers of the 

 two great empires. The northern part of the Tarbagatai chain of 

 mountains and the valley of the river Borokhandzir were included 

 in the operations, as well as the country l^eyond the river Tchou. 

 All the surveys have been mapped on a scale of 250 sagenes 



