TRANSACTIONS OF THE SKCTIOXS. 



75 



of course included in the stai'ch experiment. No. 2 was a very plump 

 English wheat, and all the others were corn of the British empire, some 

 thin and some plump grains, that sample being fullest which contained 

 least lignin, and vice versd. 



From the above it will be seen that the manufacturer would be greatly 

 deceived if he expected to obtain 60 per cent, of starch, as stated by 

 some chemists ; he would in fact seldom or never obtain more than 34. 



Kirchoff discovered that very diluted sulphuric acid would convert 

 starch to sugar of grapes, and after long boiling- Mr. Jones finds the 

 concentrated acid will produce this effect immediately. Dry starch 

 is, by addition of sulphuric acid, instantly converted into charcoal, 

 and acetic or malic acid can be distilled from the mass ; but if 1 part 

 of starch be mixed into a paste with 1 part of water, and then 2^ parts 

 of sulphuric acid added, the starch is instantly dissolved : the solution 

 has a temperature of about 200°, smelling strongly saccharine and sethe- 

 real, in fact a peculiar sether can be distilled from the solution. When the 

 solution is diluted, and the acid removed, a light- coloured deliquescent 

 sugar is obtained ; but only 63'8 parts of sugar are oljtained from 100 

 parts of starch in this way, and it would be interesting to find in what 

 form of soluble combination the other part exists, and perhaps this in- 

 quiry may tend to show the difference between starch and sugar, and 

 throw some light on isomeric bodies. 



Volatile Liquid. — When the lignin of wheat is separated in the humid 

 way, dried at a temperature of 1 00°, and mixed into a paste with water 

 to prevent charring, and sulphuric acid is then added in small quan- 

 tities at a time, the bran will be dissolved, and the solution will have a 

 dark brown colour, and a pleasant aethereal odour ; upon distilling this 

 fluid a pungent liquid is obtained, smelling of hydrocyanic acid, 

 though this cannot be detected in the solution. This fluid when rectified 

 has a specific gravity -9829 and boils at 186° Fahrenheit. When poured 

 upon caustic lime, the lime slakes and becomes of a bright yellow colour, 

 which appears to be peculiar to this fluid ; when boiled with lime-water 

 the solution becomes dark orange ; pure ammonia, potassa, and soda 

 change the brown liquid to yellow, but not orange ; the property of 

 changing lime yellow did not exist in the most volatile portion of the 

 solution only, as the liquid in the retort after distillation had that pro- 

 perty also. An acid changes the brown to yellow, which an alkali re- 

 stores, showing some analogy to the colouring matter of turmeric. Sup- 



