CHEMICAL SCIENCE. 221 



The bisulphide of nitrogen unites directly with the two chlorides of sul- 

 phur, and forms with each several distinct compounds. The authors 

 assign to three of these combinations the formulas Cl S -j- X S ' 2 , Cl 

 S -j- - N S 2 , Cl S -j- 3 N S c . Ami. de Chemie et de Physique, xxxii. 380 . 



DETONATING SUGAR. 



AT a meeting of the Academy of Turin, 1850, Prof. Sobrero an- 

 nounced his discovery of a detonating sugar, obtained from that mate- 

 rial, by means similar to the mode of preparing gun-cotton. Take 

 powdered loaf-sugar and pour on it a mixture of two volumes of sul- 

 phuric acid (at Barune 06) and one volume of nitric acid (at 43). 

 Immediately the sugar is converted into a tenacious viscid substance, 

 which is only partially dissoluble in the acids employed. On adding a 

 large quantity of water (about twenty times that of the acids employed) 

 the sugar is converted into a material witli the following properties. 

 It is very white, diffusible in the acid mixture, and absolutely insoluble 

 in water, but very soluble in alcohol and sulphuric ether. When sul> 

 ject to a moderate heat, it melts and is decomposed without detona- 

 *tion ; but if suddenly heated to redness, it explodes like gunpowder, 

 producing gaseous emanations in which it is not difficult to recognize 

 the nitrous vapor and that of cyanogen. By the blow of a hammer 

 it also explodes, but feebly. The composition of this fulminating sugar 

 it will not be difficult to determine more easily than that of gun- 

 cotton from its more slow decomposition under a graduated heat, 

 when it may be exposed to the action of oxide of copper. 



OX A MODIFICATION OF THE METHOD OF PREPARING BUTTER. 



IF butter contained only the fatty parts of milk, it would undergo 

 only very slow alteration in contact with the air. But it retains a cer- 

 tain quantity of caseum, which exists in the cream ; this caseum is 

 converted into a ferment, and this gives rise to butryric acid, to which 

 the disagreeable taste of rancid butter is owing. The washings which 

 butter is made to undergo can only imperfectly free it from this cause of 

 alteration, for the water does not moisten the butter, and cannot dissolve 

 the caseum, rendered insoluble under the influence of the acids which 

 are developed in cream. A more complete purification may be arrived 

 at by saturating these acids ; the caseum would then again become 

 soluble, and, consequently, the butter would retain only very small 

 quantities , which would be removed almost entirely by washing. 



The following method of proceeding is proposed by M. Chalambel : 

 when the cream has been placed in the churn, pour in, by small por- 

 tions at a time, and agitating the while, a sufficient quantity of milk 

 of lime to entirely destroy the acidity ; churn the cream until the but- 

 ter is separated ; it must not be expected that it will collect in lumps, 

 as it generally does ; decant the butter-milk, and continue to churn 

 until it is sufficiently collected. By this method better products inay 

 be obtained, capable of being preserved for a longer time, than those 

 obtained by the coaimoa processes. Butter, which has become rancid, 



10* 



