SUGAR 



947 



possible, when the plug and the inner tube are brought into the proper position, A, 



fig. 1935, to fill the cavity of the rod with the syrup, and to take it out without 



allowing any air to enter. In 



order to facilitate the turning 1936 1935 



of the inner tube within the 



outer, there is a groove in the 



under part, into which a little 



grease may be introduced. 



Whenever a proof has been 

 taken, the plug must be placed 

 in reference to the inner tube, 

 as shown in fig. 1935, c, and 

 then turned into the position 

 A; when the cavity of the 

 plug will again be filled 

 with syrup, c must now be 

 turned back to the former 

 position, whereby all inter- 

 course with the vacuum-pan 

 is cut off; the plug being drawn out a little, and placed out of communication with 

 the inner tube. The plug is then turned into the position B, drawn out, and tho 

 proof examined by the fingers. 



The method of using the vacuum-pan varies with the character of the grain 

 required to be produced. On commencing boiling, the syrup should be run in as 

 quickly as possible, till the whole heating-surface is covered, when tho steam is 

 turned on, and the evaporation conducted at a temperature of from 170 to 180 

 Fahr. As soon as the syrup begins to granulate, the temperature becomes reduced to 

 160; and finally just before the evaporation is completed, and the sugar ready to be 

 discharged into the heater, it is further reduced, and approaches 145, being the 

 lowest temperature at which proof-sugar boils, 3 inches from a perfect vacuum. 

 When the sugar-boiler ascertains, by withdrawing a sample of the syrup by means 

 of the proof-stick, and examining it against the light between his finger and thumb, 

 that the crystals are in a sufficiently forward state for his purpose, he adds another 

 measureful to that already in the pan, and the same process is repeated till the 

 whole charge has been admitted. After each successive charge the crystals continue 

 increasing in size to the end of the operation, those first formed acting as nuclei : a 

 skip, as it is technically called, or a panful of tho concentrated sugar, may be made 

 in from two to four hours from the commencement of the boiling. If a fine-grain 

 sugar be required, greater quantities of syrup are admitted at each charge of the 

 measure, and vice versa. 



Making of Loaf-sugar. The proof-sugar at a temperature not exceeding 145 is 

 then let down through a cock or valve in the bottom of the pan into the heater. The 

 sugar-liquor consists at this stage of the process of a large number of small crystals 

 floating in a medium of syrup. 



The heater is an open copper pan of about the same capacity as the vacuum-pan, 

 and is furnished with a steam-jacket and provided with an agitator, in fact, it closely 

 resembles the dissolving-pan used for the first process. The object to be attained in 

 the heater is to raise the sugar to a temperature of 180, which has been found by 

 practice to be the point best adapted for hardening and completing the formation of 

 the crystals, during which process the sugar is constantly stirred. 



The sugar is then run out through a cock in the bottom of the heater into a ladle, 

 from whence it is poured into moulds or cones of sheet iron strongly painted. The 

 sizes of the moulds vary, from a capacity of 10-lb. loaves to that of 56-lb. bastards 

 a kind of soft brown sugar obtained by the concentration of the inferior syrups. 

 These moulds have the orifices at their tips closed with nails inserted through pieces 

 of cloth or India-rubber, and are set up in rows close to each other, in an apartment 

 adjoining the heaters. Here they are left several hours, commonly the whole night, 

 after being filled, till their contents become solid, and they are lifted next morning 

 into an upper floor, kept at a temperature of about 100 by means of steam-pipes, 

 and placed over gutters to receive the syrup drainings ; the plugs being first removed, 

 and a steel wire, called ' a piercer,' being thrust up to clear away any concretion from 

 the tip. The syrup which flows off spontaneously is called ' green syrup.' It is kept 

 separate. In the course of one or two days, when the drainage is nearly complete, 

 some finely-clarified syrup, made from a filtered solution of fine raw sugar is poured 

 to the depth of about an inch upon the base of each cone, the surface having been 

 previously rendered level and solid by an iron tool, called a ' bottoming trowel.' The 

 liquor, in percolating downwards, being already a saturated syrup, can dissolve none 



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