50 



again to boil, that it should be constantly stirred to prevent 

 the precipitation of the ingredients, the ebullition must be 

 kept up for a few minutes and the sirup is then prepared 

 for filtration. 



FILTRATION. 



This is an exceedingly simple operation, a flannel cloth 

 fixed to a frame is all that is required. 



Sirup at the density of 30° cold, as it comes from the fil- 

 terer is not sufficiently concentrated to crystalize, it is there- 

 fore necessary to submit it to another boiling to evaporate 

 the superabundant water it still contains, and so to pro- 

 duce the required crystalization. 



This operation is only a continuation of the concentrating 

 process and also its completion ; the same boiler which is 

 suitable for the first part of this process is the one now 

 again required, the fire must be carefully attended to, the 

 sirup skimmed when required, and if it rises in foam, must 

 be stopped as before by a piece of grease : when the proof 

 shows 90 1-2 to 91 of Reaumor, 236° Fahrenheit which 

 point it may reach, if the sirup is very good, it is time to 

 stop and empty the boiler ; it would be more prudent to do so 

 at 89 1-2, the sugar would purify more easily and as the 

 molasses must necessarily be reboiled, this supports the op- 

 eration all the better for being a little richer in sugar. 



The 16 1-2 gallons with which we began our experiment 

 will now be reduced to 10 1-2 gallons. In this state it may 

 be turned into a vessel to cool gradually, where it may stay 

 for 10 or 12 hours when it will fall to the temperature of 

 170° or 180° of Fahre?iheii., and then may be put into the pots 

 for crystalization, these usually contain 6 to 8 gallons, in turn- 

 ing it into these, masses of the crystals will be found already 

 at the bottom and sides of the vessel, if the sirup is good, some 



