RECAPITULATION AND REMARKS. 



127 



and filtration from the impurities contained in it, and be 

 brought as nearly as possible to a pure solution of sugar 

 and water. 4. That defecation, filtration, and evaporation 

 to the density of from 28° to 32° Beaunie, follow each other 

 with the greatest possible rapidity. 5. That after this point 

 has been arrived at, the concentration should be completed 

 at a temperature not exceeding 180° F., but if possible at 

 160° F., which can be accomplished most certainly in vacuo; 

 but with ease, by proper skill and attention, in many of the 

 other pans invented for this purpose. 6. That crystalliza- 

 tion should be promoted by keeping the sugar for some 

 time at a temperature of 180° F., that being the tempera- 

 ture most favourable for this operation ; and that the curing 

 house, or rooms in which the sugar is crystallized and 

 drained, should be dry, well lighted, and provided with the 

 means of artificially raising the temperature of the air con- 

 tained in them. 7. That the melasses or syrup from the 

 first sugars should be reboiled every day as fast as collected, 

 as the salts and other impurities contained in it speedily 

 effect a chemical change, which results in the total loss of 

 a large proportion of the crystallizable sugar contained in 

 it, and which, by a farther concentration, is readily pro- 

 cured. 8. That in all the above operations the most rigid 

 cleanliness be observed ; that the mill, the gutters, and 

 sieves be all constantly purified by repeated washings with 

 boiling water ; that the defecating and evaporating vessels 

 be always scoured perfectly bright ; and that the drains or 

 gutters which convey the melasses from the first sugars, 



