302 Notice of some Recent 



tact with 12 # 25 parts of diatase dissolved in 367 parts of 

 cold water, when preserved at a temperature of 68° for 24 

 hours, produced 77-64 parts of sugar. 6th. The same ex- 

 periment repeated at the temperature of melting ice gave, 

 at the end of two hours, 11*82 sugar. 7th. Between 10° 

 and 23° starch paste is rendered fluid without the production 

 of sugar. 8th. The most favourable proportions and cir- 

 cumstances for the production of a great quantity of sugar 

 are a slight excess of a diatase or sprouted barley, about 

 50 parts of water to one of starch, and a temperature be- 

 tween 140° and 149°. 9th. Starch-sugar prepared either 

 with diatase or sulphuric acid crystallizes in cauliflower 

 like forms, or in prisms with rhomboidal faces. It has the 

 same composition as grape-sugar. 10th. Diatase even in 

 excess does not convert into sugar gummy matter dissolved 

 in water with starch-sugar, but when this matter is isolated 

 it converts it almost completely into sugar. 11th. Diatase 

 produces no effect on gum arabic, cane sugar, nor sugar of 

 yest. 12th. A solution of diatase in water decomposes in 

 the air. 13th. When sugar of starch, obtained either by 

 sulphuric acid or diatase, is submitted to the spirituous fer- 

 mentation, the sum of the weight of the alcohol, carbonic 

 acid and water of crystallization differs from the weight of 

 the sugar by about three and a half hundreths, proceeding 

 from the formation of acetic and lactic acids, &c. 14th. To 

 determine as exactly as possible the quantity of alcohol in 

 a liquid containing a substance which retains the alcohol 

 strongly, it is necessary to push the distillation until the 

 liquid passing over no longer affects the centesimal areo- 

 meter. — (Journ. de Ckim. Medic, i.) 



X. Method of colouring ornaments of gold. — Manufacturers 

 possess a number of receipts for colouring ornaments, but 

 the following is most commonly employed : 2 parts of salt- 

 petre are mixed with 1 part of sea-salt and 1 part of Roman 

 alum, in a quantity of this mixture equivalent to about 

 three times the weight of the ornaments to be coloured, 

 dissolved in boiling water so as form a very concentrated 

 solution where the ornaments are placed. This solution is 

 called the sauce. Here they remain at a boiling tempera- 

 ture for 15 or 25 minutes, according to the shade to be 

 given them ; they are then washed in pure water and the 

 operation terminates. If lustre is required, they are after- 



