CHEMISTRY. 195 



CARAMEL COLORS. 



In London caramel is made by roasting sugar of coarse de- 

 scription in cylinders similar to those used for roasting coffee, 

 chiccory, and cocoa ; this yields a very inferior preparation both 

 for coloring as well as for admixture with coffee. So prepared it 

 contains assamar and other pyrogenetic products which are very 

 bitter. On the continent apples of inferior description are 

 treated as described, yielding a product superior to that obtained 

 from sugar. Sugar, however, is the only fit material to prepare 

 caramel, and for this purpose the sugar is best heated in capa- 

 cious, roomy vessels made of copper (in Vienna copper lined with 

 silver is preferred), the vessel containing the sugar being placed 

 in an oil bath containing a thermometer to indicate the tempera- 

 ture. The latter must not be below 410 nor above 428 F. The 

 heating of the sugar is continued as long as aqueous vapors are 

 given off. The crude caramel so obtained is best purified by 

 being placed upon a parchment paper dialyser, which is placed 

 on water. The undecomposed sugar and intermediate com- 

 pounds are thus got rid of; they dissolve out with facility, and 

 what remains on the filter is, weight for weight, five times as 

 strong in coloring matter as the crude caramel. While the sugar 

 is being exposed to heat it is preferable 4 to stir it with a spatula. 



Another mode of obtaining pure caramel, free from bitter 

 produce (assamar and the like), is to heat the sugar as above, 

 and to treat the powdered caramel with alcohol (pure methylated 

 spirits) , to digest it for 3 to 4 hours therewith, and repeat this till all 

 bitter^taste is gone.. An aqueous solution containing 10 per cent, 

 of purified caramel is gummy, and forms a jelly. When a solu- 

 tion of caramel in water is evaporated in vacua (small vacuum 

 pan as used in sugar refineries), it dries up to a black shining 

 mass, freely soluble again in water, hot or cold ; but if the solu- 

 tion is evaporated on a water-bath to dryness in contact with air, 

 the whole mass becomes insoluble in water either hot or cold. 



A very small proportion of caramel gives to a large bulk of 

 water the dark-brown tinge known as sepia. An impure but 

 pretty strong solution of crude caramel (that is, not purified by 

 dialysis or alcohol hence the term impure for the solution) is 

 sold in London under the name of cotfeena in small bottles at Is. 

 per bottle, to be had in many oil and color shops in the metropo- 

 lis ; it is use$ in teaspooufuls to improve coffee, dispensing with 

 chiccory. Treacle is not very manageable to use for the making 

 of caramel. The sugars should be first dried at 212 F. On the 

 continent dry glucose is sometimes used instead of cane or beet- 

 root sugar for the purpose of making caramel. Chemical News. 



NEW CHEMICAL TOY. 



" Pharaoh's serpents" and " Vesuvian tea" have paved the way 

 for the reception of a new Chinese wonder in the shape of "ferns 

 growing out of burning paper." This is a neat little experiment, 

 free from many of the disadvantages appertaining both to the 



