YACUUM PAXS. 351 



than Avill be necessary on another plantation to make three thousand 

 barrels where the fire trams are used. 



The advantage of the vacuum pan system, in respect to expense of 

 fuel, is immense; as the vacuum pan is worked by means of exhaust 

 steam from the various engines and pumps of the sugar house, thus 

 taking advantage of the latent heat in the boiling of the sugar, after 

 the steam has done its duty as prime mover. 



Thus it will be seen that the employment of the vacuum pan and 

 triple effect does not materially increase the amount of fuel necessary 

 for the engines. 



The situation of the pan in the house is important, f tr upon its po- 

 sition depends the economical working of the sugar house. 



Employing this system, the planter can have packed in boxes or 

 barrels, and many times in the market each day, the sugar made on 

 the previous day. With the vacuum pan only can be obtained a grain 

 of sufficient consistence to resist the extraordinary expulsive force of 

 the centrifugal. 



With a well arranged boiling house, it is not necessary to touch the 

 juice after it leaves the mill until sugar, dry and well purged, comes 

 from the centrifugal, which all planters must acknowledge is a great 

 economy of labor, time, and money. 



The pans can be put upon the beams of building, but the better 

 way is to place them upon iron columns and platform, independent of 

 building, so they will not be shaken by the high winds that visit sugar 

 countries. 



In the vacuum pan system, the amount of fuel saved is considerable, 

 and the difference in the amount of molasses obtained from a given 

 amount of juice is as 2 to 3 — that is, the train produces three hogs- 

 head of sugar and one of molasses ; the vacuum pan produces five, or 

 even seven, hogsheads of sugar to one of molasses. 



