CHEMICAL SCIENCE. 333 



use. As a raw material for the production of spirit, for which it seems well 

 adapted, the glucose of the Sorghum may prove valuable, and as an addition 

 to a forage crop, the plant may be found to possess a high agricultural im- 

 portance. 



Dr. John Bacon made a statement confirmatory of the results arrived at 

 hv Dr. Haves. He was unable to obtain any crystals of cane surrar. 



J ft / * 



A private note of Dr. Hayes, received by the editor since the communica- 

 tion of the above paper, states that the glucose sugar of the sorghum, after ex- 

 traction and standing several months, takes a crystalline form. The crys- 

 tals formed resemble those of cane sugar, but the product itself remains a 

 higher grade of dry fruit sugar. 



Dr. Hayes also states, that the sorghum, when grown in Algeria, undoubt- 

 edly secretes cane sugar the climatic influences being altogether different 

 from those to which the plant is subjected in the United States. 



OX A NEW APPLICATION OF ALUMINA. 



All chemists know the property which hydrated alumina possesses of 

 uniting with coloring matters and forming true combinations commonly 

 known under the name of lakes. These compounds, although not yet 

 studied, ought to have, constant composition, for we know certain salts of 

 these coloring matters with other bases ; for instance, carmine forms with 

 the oxide of copper a definite substance, and alizarine forms with potash a 

 definite substance; and M. Mene', chemist to the metallurgical establish- 

 ment of Cruczot, seeing this property and the power of hydrated alumina to 

 decolorize liquids, thought whether its use might not be extended to some 

 more branches of industry. 



/ 



He prepared the hydrated alumina by decomposing a solution of alum 

 with carbonate of soda, washing the precipitate in a filter. This alumina 

 was mixed with boiling solutions of coloring matters, the alumina always 

 being in excess, and a colored lake was obtained, precipitated at the bottom 

 of a colorless liquid. The experiments were first made upon solutions of 

 litmus and upon carmine, and extended to molasses and colored syrups. 

 The experiments were so successful that the author hopes, owing to the. 

 simplicity of the operation, that it will be possible to substitute it, or the 

 salts of alumina, in place of animal charcoal in decolorizing sugars. 



To decolorize the syrup of sugar, at present, the syrup is made to flow 

 very slowly through tubes containing large quantities of animal charcoal, 

 and the operation is more or less quick in proportion as the solution is more 

 or less concentrated ; whilst by means of alumina there is only one boiling 

 rcqured, and on leaving the apparatus the sugar can crystallize out of it. 

 A simple cloth filter stops the lakes formed by the impurities of the syrup. 

 The revivification of the alumina salt would be trifling compared with 

 that of animal charcoal. The results of the experiments were as follows : 



10 grains litmus were discolored by 250 grains animal charcoal 

 10 " " 15 " alumina 



