390 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



appear, especially on clihition with water. Otlier kiuda of sug^ar remain 

 indifferent to the bichromate ; and the presence of starch sugar prevents 

 the production of this green color. Nitrate of cobalt, added to cane sugar 

 alkalized, produces a bluish violet precipitate ; but not with an alkalized 

 (potash) grape sugar. 



The adulteration of sugar by substances wliich are insoluble in water, 

 as sand, chalk, etc., are so easily detected as not to require much con- 

 sideration. 



It has been estimated by reliable authoritj' that not less than 40,000,000 

 pounds of foreign substances are annually mixed with the sugar consumed 

 in Great Britain. 



We very seldom think or speak of sugar except in connection with 

 articles of diet and confectionary ; but its applications and use in processes 

 of arts are of considerable importance. It would not be easy to find a sub- 

 stitute for the glue and treacle roller employed for inking the types for 

 printing. It is also employed in copy-inks, and for exploding infernal 

 machines, in connection with other ingredients. And when mixed in an 

 iron spatula in the proportions of one part of sugar and three parts of alum, 

 and heated over a fire until perfectly dry and reduced to a blackish carbo- 

 naceous substance ; then transferred to a retort and heated till a bluish 

 flame appears at the neck of the retort, and thus continued for a quarter of 

 an hour, and allowed to gradually cool, a pyropliorus of very peculiar pro- 

 perties is formed, and which when exposed to air produces intense heat. 



Sugar of acid fruits has for its formula C,,, Hj,, 0„. 



Grape sugar has a formula of C,j, Hu, Ou; when crystalized its formula 

 is Cij, H,4, Oi4. 



It is the same substance found in dry grapes or raisins, in the form of 

 white grains. 



The urine of patients laboring under a peculiar disease called diabetes, 

 contains sometimes ten per cent, of sugar, the chemical properties of which 

 are identical with grape sugar. The sugar obtained when starch is boiled 

 with a weak solution of sulphuric acid, and the solution evaporated, after 

 having been saturated with chalk, is identical with grape sugar, but it is 

 generally called glucose. The granular sugar found in honey is identical 

 also with grape sugar. 



Grape sugar crystalizes with much more difficulty than cane sugar, 

 always producing a compound crystalization; and it is less soluble in water 

 than cane sugar, requiring one and a half parts of cold water to dissolve 

 one part of grape sugar. The sweetening power of grape sugar, com- 

 pared with cane sugar, is, according to Dumas, as 40 to 100. It dissolves 

 more freely in alcohol than cane sugar, one part dissolving in 60 parts of 

 boiling absolute alcohol. It is completely liquefied at 212" and loses two 

 equivalents of water, and is converted into a new sugar of which the for- 

 mula is the same as that of fruit sugar, viz: Ci„ Hi„ Oi,. 



If slaked lime be poured into a solution of grape sugar, a large quantity 

 of the lime is dissolved, and the liquor first exerts an alkaline reaction, 

 but at a later period becomes neutral and carbonic acid no longer forms a 

 precipitate. The sugar is then converted into a powerful acid called glucic, 



