CULTIVATION OF PLANTS. 199 



rasp. This is a wooden barrel, set transversely with steel saws at half an inch 

 apart. It is 13j inches wide, and 23 inches diameter, and when propelled by 

 steam, makes about 900 revolutions in a minute, crushing into impalpable 

 pulp 90 pounds of roots in that space of time. Pressing by cylinders has 

 often been tried, but found to be totally inapplicable to the purpose. 



3. Pressing the Pulp. The heat engendered by the process of rasping brings 

 on instantaneous fermentation, which is destructive to the yield of sugar: no 

 time is therefore lost in submitting the pulp to the action of the press, by which 

 the juice is extracted in a surprisingly short space of time. In no instance did 

 I witness this operation performed^by any bin hydraulic* pressure, the power 

 of which is astonishingly great. The machine for this purpose is very ex- 

 pensive, but when obtained, the saving of labour and time is great. The pulp 

 falls from the rasp into a square box below, from whence it is taken in a deep 

 "wooden of copper shovel, and put into a bag which is held open for its recep- 

 tion; it is then placed upon a frame of wicker work, standing upon a small 

 hand-barrow resting upon wheels, where it is spread evenly in the bag, and 

 the mouth is then turned down to prevent the escape of the pulp while under 

 the press; it is then covered by another wicker frame and another bag, until 

 the pile consists of thirty-five bags and wicker frames. The whole is then 

 removed to the press, where a man takes and deposites them on the wooden 

 platform, which sets on the bed of the press, and the pressure is then applied. 

 So soon as the juice is extracted, the pressure is taken off, the bags are emptied 

 of the dry cakes, and the press is ready for another load. These presses are 

 always worked in pairs, so that while one is pressing, the other is being load- 

 ed. The juice flows from the press into a cistern beneath the floor, from 

 whence it is immediately pumped into the desiccating pan, which is placed so 

 high, that the contents might flow from it by a pipe, into the evaporator. 



4. Desiccation. The desiccator is a copper pan, into which the juice is pump- 

 ed, so as to fill it within four inches of the top, when heat is applied, either by 

 means of steam or fire. As soon as the juice has attained the heat of 58 W 

 Reaumur (162$ Fahrenheit) lime is added in exact proportion to the acid 

 contained in it, which is ascertained by chemical tests. This lime is prepared 

 by slaking with hot water and mixing, so as to be of the consistence of cream, 

 and when it is added, the greatest care is taken to mix it most intimately with 

 the juice, by stirring with a wooden spatula: after this, it is suffered to rest, 

 and the heat is raised to the boiling point, when it is suddenly checked by 

 withdrawing the steam or fire; as soon as the juice has become perfectly clear, 

 it is run off into the first evaporator, taking care that none of the scum, or 

 sediment at the bottom of the pan passes with it. The scum and sediment is 

 then collected, put into bags and pressed, to obtain all the juice it contains; 

 after which, the residuum is thrown to the dunghill, a valuable manure. 



5. Evaporation. The evaporator is a copper pan, into which the clear def- 

 ficated liquor flows, until the pan is about a third part full; to this, a small 

 quantity of animal charcoal is added, and the fire or steam is applied; here it 

 is boiled until it marks 21 by the saccharometer, when it is passed into a rer 

 ceiver, from whence it flows into the clarifiers for purification. During the 

 boiling, if the juice rises in the pan so as to threaten to overflow, a small quan- 

 tity of tallow is added, which causes an immediate subsidence, and facilitates 

 evaporation. 



6. Clarifying. The clarifiers are wooden or copper pans, 2 feet 8 inches 

 deep, 20 inches diameter at top, 11 inches diameter at bottom, each with a 

 small brass cock near the bottom. A copper strainer standing on three feet 

 and covered with canvass, is placed in the bottom of each clarifier, which is 

 then filled with granulated animal charcoal, (about 100 Ibs. in each pan,) and 

 is covered with another copper strainer and cloth, and then the syrup is per- 

 mitted to flow upon it until the pan is full. After it has stood some time, the 

 cock is opened, the syrup is permitted to flow slowly into a cistern, and the 

 pans are refilled as fast as they empty. From the cistern the syrup is pumped 



* The great variety of power presses to be obtained in this country, at com- 

 paratively small cost, will obviate the necessity of always using the hydraulic 

 press. Pub. Com. 



