SUGAR FROM STARCH. 3J9 



XIV. 



Letter from Dr. Tutkill on the Sugar from Folato Starch. 



To Mr. Nicholson. 

 DEAR SIR, 

 VING learned, that professor Berzellus had brought loveation of 



HI 



intelligence to this country of a very remarkable change sugar froni 

 produced in wheat starch by the action of dilute sulphuric 

 acid at a high temperature, as discovered by M. KirchotF, of. 

 the imperial academy of St, Petersburgh, I was desirous of as- 

 certaining whether the fsecula of other vegetables, submitted 

 to the action of the same fluid, at the same temperature, would 

 exhibit a similar phenomenon. For this purpose I took eight potat^ starch, 

 pounds and three quarters of potaloes, grated them, and placed 

 the pulp on a sieve. Cold water was then slowly poured upon 

 this pulp as long as it passed turbid through the sieve, and the 

 liquor was suffered to stand in the vessel that received it till it 

 became clear. On pouring oft the clear liquor, the fsecula of 

 the' potatoes was found at the bottom of the vessel j and, when 

 dried by a very gentle heat, weighed a pound and a hzlf. To 

 this fsecula were added six pints of distilled water, and a quar- 

 ter of an ounce by weight of common sulphuric acid in an 

 earthen vessel furnished with a cover. The mixture was kept a pound and a 



boilinff for thirty-four hours without intermission, the vessel ^^^j °^ starch, 

 , . r , ^^"^ *'^ pints 



being covered, and the loss by evaporation carefully supplied by of water, and 



the frequent addition of distilled water, so as to preserve the same °^^ quarter of 



' . T^ 1 /: an ounce of 



quantity as at the commencement of the operation. For the nrst sulphuric acid 



twelve hours I could perceive no change in the sensible proper- were gently 



ties of the vapour. At the expiration of twenty-four hours the {Q^^^ hours. 



liquor Iiad evidently become saccharine, and this quality conti- in twenty four 



nuedto increase as the boiling was prolonged. Thirty-four ^»o""t^^f ^^^'^ 



hours after the commencement of the ebullition, half an ounce j-i^e. 



of finely-powdered charcoal was added, and the boiling con- After 34 hour* 



tinned for two hours longer. The acid was then saturated by J^^"""^^"*? ^ 



lime that had been very recently burned, and the boiling con- coalwasadded. 



tioued for half an hour; after which the liquor was passed After two 



through a piece of calico, and the substance remaining on the J^jj"^"'"^^/',^ 



filter washed by the repeated cflusion of warm water. This rated by lime. 



substance, when dry, weighed seven eighths of an ounce, and in5oiui,ic pre- 



consisted of charcoal and sulphate of lime. The clear liquor cipitate. 



wa€ now evaporated in a water bjyh to the consistence o^ si- g^-aporaTcd! 



rup, 



