CHEMISTRY. 



103 



beam. On repeating this experiment with a 

 condensed beam of light forming a cone eight 

 inches long, the cone, which was at first invis- 

 ible, flashed suddenly like a luminous spear. 

 The rapidity of the condensing action dimin- 

 ished with the density of the light. The same 

 effects were produced when oxygen or hydro- 

 gen was employed as a carrier ; when the head 

 of the beam was sifted out through a plate 

 of alum, or when the beam was used without 

 sifting. That the amylic nitrite undergoes de- 

 composition is proved by the formation of brown 

 fumes of nitrous acid. Sunlight produces sim- 

 ilar effects. The author proves, in the next 

 place, that the decomposition is effected by the 

 more refrangible rays of light, and that liquid 

 amylic nitrite is most potent in arresting the 

 rays which affect its vapor. This seems to 

 show that the absorption takes place in the 

 atoms, and not in the molecules. The author 

 anticipates wide, if not entire, generality for 

 the fact that a liquid and its vapor absorb the 

 same rays. When the tube is filled with a rare 

 and well-mixed vapor, the electric light devel- 

 ops a blue color, which may be pure and deep, 

 or milky, according to the intensity of the light. 

 The author connects this result with that of 

 Brucke's experiments on the colors of the sky. 

 Various other liquids were tried with success. 

 In many cases the condensed vapors formed 

 extremely beautiful and regularly - shaped 

 clouds, the particles rotating around the axes 

 of the tube, or round other axes. The most 

 beautiful forms appear to have been those pro- 

 duced by iodhydric acid. (American Journal 

 of Science, January, 1869.) 



White Gunpowder. The Mechanics' Maga- 

 zine, of August 7, 1868, speaks in terms of ap- 

 proval of white gunpowder, on account of the 

 comparative safety of its manufacture and use, 

 and its 'superior effectiveness as an explosive 

 material. This substance is a white, impalpa- 

 ble powder, resembling flour, powdered chalk, 

 or magnesia, in its superficial appearance. Its 

 composition is as follows : 



Chlorate of potash 48 



Yellow prussiate of potash 29 



Finest loaf-sugar 23 



100 



In manufacturing it the yellow prussiate 

 must be dried in an iron ladle until it is as 

 white as the chlorate. The ingredients are 

 ground separately to very fine powder, and 

 then mixed by means of a conical sieve, until 

 they are thoroughly incorporated, but not by 

 trituration. For small quantities a common 

 "Wedgwood mortar and pestle may be used, 

 but they must be kept perfectly dry and clean. 

 The operation of mixing does not take many 

 minutes, and with these precautions is abso- 

 lutely free from danger. In loading, it is treat- 

 ed the same way as ordinary gunpowder, being 

 pressed down by hand, solid, but not hard. 

 The charge is ignited in the usual way, either 

 with a common cap or nipple, or on a rim or 



central-fire cartridge. No alteration is required 

 in fire-arms in order to use it, but the car- 

 tridge-case must be little more than half its 

 usual length, which wall give the same result 

 as double the quantity of ordinary gunpowder, 

 but with greater quickness, penetration, and 

 accuracy. It produces neither smoke nor 

 flash of flame at the muzzle, on discharge, and 

 can be used in a casemate with perfect com- 

 fort to the gunners. In actual use it does not 

 appear to possess a bursting so much as a pro- 

 pulsive power. The economy of the powder 

 is apparent when it is stated that its wholesale 

 cost is about 86 s. per cwt., but, as its strength 

 is said to be at least one-third greater then 

 than that of ordinary powder, its cost may be 

 comparatively estimated at about 60s. per cwt. 

 Mr. Henry W. Reveley, 0. E., the manufacturer 

 of the white gunpowder (unpatented), has not 

 been able to procure a practical trial of it from 

 the Royal Ordnance department. A sample 

 of three dozen rounds of Enfield cartridges, 

 which he sent to the department for trial, 

 were returned to him, in the original package 

 with the seal unbroken, accompanied by a 

 note, stating that the cartridges were not suit- 

 able for military purposes. The officials had 

 evidently decided about them without even 

 looking at them. 



Nitroglucose. The American Journal of 

 Science, 'for May, 1868, contains a paper upon 

 this compound from the pen of Mr. M. Carey 

 Lea. He prepares the article in the following 

 way: two ounces of fuming sulphuric acid, 

 two of common sulphuric acid, two of strong 

 nitric acid are mixed. Sugar is stirred into 

 this in the form of powder, to a thin paste. 

 The stirring is kept up, and as fast as the 

 nitroglucose separates in doughy masses, it is 

 removed with a spatula, and thrown into cold 

 water. More sugar being added will give 

 more nitroglucose, but considerably less in 

 proportion than the first addition. As soon as 

 possible the nitroglucose must be kneaded up 

 with cold water to get the acid out ; otherwise 

 (in ten or fifteen minutes) it passes to a green- 

 ish color, and decomposition commences : The 

 removal of the adhering acid is much more 

 difficult than in the case of peroxylin, and is 

 an extremely disagreeable operation. The 

 acid pervades the whole of the doughy mass 

 so fully, that the fingers are stained and 

 burned by it, nor can the whole of the acid 

 be removed satisfactorily in this way. The 

 best means found by the author was, to dis- 

 solve the crude nitroglucose in a mixture of 

 alcohol and ether, and then to pour this into 

 a large quantity of cold water with constant 

 stirring, and violent agitation afterward. The 

 method is not altogether satisfactory, and 

 seems to be attended with some loss of mate- 

 rial. Prepared in this way, nitroglucose is a 

 white lustrous body, which may either as- 

 sume the doughy amorphous condition, or the 

 crystalline, and passes from one to the other 

 with extreme ease. "When first formed by the 



