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SCIENTIFIC INTELLIGENCE. 



METEOROLOGY. 



1. Unctiwus Dew. — In the neighbourhood of Rotterdam, it 

 has been recently observed, that the morning dews, instead of 

 being pure and hmpid, are of an unctuous consistency. 



CHEMISTRY. 



2. The New Vacuum Sugar.— The grains of this beautiful 

 sugar are true and well-formed crystals. They do not melt so 

 readily as common sugar, — a circumstance that induces some 

 inaccurate observers to imagine that this sugar is not so sweet 

 as common muscovada. Thetasteisjustthat of fine c^wdz/. The 

 advantage is, that this sugar is far less hygrometric than common 

 raw sugar, and suffers less from a moist atmosphere. The ap- 

 paratus used in its preparation is a modification of the late Mr 

 Howard's apparatus for boiling sugar in vacuo; with strainers 

 of copper-plates pierced with minute holes, or several folds of 

 wire-gauze for clarifying the syrup. The process is, imme- 

 diately on crushing the canes, to heat, lime, and scum the 

 juice, which, while warm, is forced through the strainer, from 

 which it runs into the boilers. These are provided with air- 

 tight covers, the tops of which are connected by tubes with a 

 large air-pump, wrought by a steam engine. The steam, as 

 generated, is thus drawn off, and the boihng is carried on at a 

 temperature far below the boiling point of sugar. When suf- 

 ficiently concentrated, the syrup is crystallized, and, when con- 

 solidated, it is carried to the curing-house, the temperature of 

 which is kept up by steam-pipes running into it. This process 

 saves much sugar, for the heating being low, little or no molasses 

 are formed, and a large quantity of sugar is obtained, which, in 

 the old process, is converted into molasses. This apparatus 

 was adopted by sugar-growers in Demerara, on the suggestion 

 of a distinguished philosopher in Liverpool. The experiment 

 has succeeded admirably; and the sugar bears a premium in 

 the Liverpool market, especially when required for coffee. 



