CAROMEL BROWN SUGAR. 315 



certain proportion of formic acid, and a brown sparingly 

 soluble substance termed ulmine. To prevent such changes 

 in the cane-juice it is usual to add to it a small proportion of 

 lime before it is subjected to heat. 



Sugar has some remarkable effects on oxides of metallic 

 bodies, the most important of which is the property of syrup 

 to dissolve lime in large proportion. 



The effect of heat on sugar deserves attention. Cane-sugar, 

 when exposed to a considerable heat, undergoes fusion, and 

 when cooled forms the article well known as barley-sugar. 

 When long kept in this form it loses its transparency and 

 becomes crystallised. When cane-sugar is still more heated, 

 it undergoes a change in its ultimate constitution, and passes 

 into a brown, deliquescent, nearly tasteless mass known as 

 caromel. The change that takes place on the ultimate consti- 

 tution of the sugar is the loss of two atoms of water, so that 

 caromel consists of 12 atoms carbon and 9 atoms of water. 

 Caromel is used by cooks and confectioners as a colouring 

 matter. When sugar is still more heated it gives off inflam- 

 mable gases, and is converted into a brilliant porous mass of 

 charcoal. 



Brown sugar is an impure variety of cane-sugar. There are 

 two varieties namely, muscovado, called raw sugar ; and also 

 foot-sugar and bastard, which last is a finer kind. The colour 

 of raw sugar is owing to the presence of uncrystallisable sugar 

 or treacle. Lime may be detected in it by oxalic acid. Sub- 

 phosphate of lime, glutinous and gummy matters, and traces 

 of tannic acid, are also present in brown sugar. Brown sugar 

 is said to be extensively adulterated with sugars prepared 

 from potato-starch and from sago-flour. The purest form of 

 coloured sugar is the crystal sugar (brought chiefly from Deme- 

 rara) employed for sweetening coffee. 



Molasses Treacle. The brown saccharine viscid fluid 



