CHEMICAL SCIENCE. 249 



solid residue of the explosion of the powder exert a sensible tension, is wholly 

 unfounded; since this residue does not boil' at the temperature of hydrogen 

 burning in air, which is 3259 C., and its tension even at that temperaturo 

 cannot, therefore, equal a single atmosphere. The authors next calculate the 

 pressure in atmospheres which the powder exerts at the moment of explo- 

 sion, and find it 4373'6, of which about 1000 are due to the expansion of the 

 solid residue. The pressure which the powder employed could exert upon the 

 sides of a cannon, would, as these results show, never exceed 4 1-2 thousand 

 atmospheres. Hence it appears that the statements of the best authorities 

 on artillery, that this pressure amounts to 50,000 or 100,000 atmospheres, are 

 entirely without foundation in fact. One kilogram of the powder employed 

 could exert in its explosion a theoretical work of 67410 meterkilograms. 

 Pogg. Ann., cii, 321. 



ALCOHOL FROM SORGHUM. 



M. Leplay, of France, has recently published the results of a protracted 

 research upon the sorghum. He has recognized: 1st, that the quantity of 

 solid matter which the stems of sorghum give in drying augments gradually 

 and quite regularly, from the formation of the panicle (flowering) to the 

 maturity of the grain, whatever the soil; 2d, this solid matter accumulates 

 in the juice and not in the insoluble part of the plant; 3d, when the stem is 

 still green, and the panicle scarcely formed, it contains only a little sugar; 

 the sugar is developed as the plant advances and the grain approaches 

 maturity, and hence the composition of the stem and the production of the 

 saccharine matter depend entirely on the state of the plant, and not on the 

 epoch of its cultivation ; 4th, in the juice of the sorghum, before its maturity, 

 in which the saccharimeter can discover little or no sugar, fermentation in- 

 dicates between thirty-two and one hundred grammes of sugar per litre ; but 

 as the grain advances towards maturity, there is a gradually increasing de- 

 viation to the right in the polarizing apparatus, caused by the cane sugar 

 present; and when the grain is ripe, the quantity of cane sugar indicated by 

 the polarizing apparatus is but little less than the sugar indicated by the 

 fermentation. 



On desiccation, the sorghum loses seventy per cent, of its weight. In 

 this state it can be preserved, and so used in the manufacture throughout 

 the year. Mr. Leplay carries on the fabrication with little cost, and ob- 

 serves that it is easily done with apparatus that may be carried from place 

 to place. 



EXAMINATION OF ALCOHOLIC LIQUIDS TO ASCERTAIN THEIR 



ORIGIN. BY M. MOLNAR. 



According to this author, this process is applicable to alcoholic liquids 

 which have apparently no foreign odor. It consists in introducing sixty 

 grammes of the spirit to be examined into a flask containing two or three 

 decigrammes of caustic potassa dissolved in water. It is well agitated, and 

 the whole is subjected to evaporation until only five or six grammes remain. 

 Then the residue is put into a bottle with a glass stopper, and about five 

 grammes of dilute sulphuric acid are added; the characteristic odor is 

 immediately diffused ; this is especially true with regard to spirit from, grain 

 and from beet-root. 



