1837] 



FARMERS' REGISTER, 



9h 



The only ajrents used in defecating are, sulphu- 

 ric acid and lime. Great care is requisite in using 

 tlipm. 



It has been elsewhere stated, that the re-action 

 of detbcating agents ouixht to be assisted by heat ; 

 and it is on this account, that coppers, or boilers, 

 are resorted to. The l()llo\ving section describes 

 this method of defecation. 



§. 1. Butlers for Defecation. 



These vessels ought to be circular, and should 

 be formed ofcopper. Their dimensions vary with 

 the mairnitude of" the works, fiom 22S irailons to 

 570 gallons; thouirh pome preli'r a number of a 

 smaller size, saj' 40 to 50 gallons. It is agreed on 

 all hands, that the interval between the raspage 

 and the tbrmaiion ot'syrup ought to be as short as 

 possible, in order to produce the most profitable 

 results. In fact, thefric'ion occasioned by rasping 

 is necessarily accompanied by a certain portion of 

 heat, which tends to increase the action of the 

 press. Now, it is well known, how detrimental 

 the action of heat is to all organic substances, dis- 

 solved or suspended in large watery masses. This 

 action is easily discernible between the root and 

 the pulp, and then atrain between this latter and 

 the expressed juice. The chance goes on increas- 

 ing in proportion to the interval between the rasp- 

 ing and the defecation. The decomposition has 

 often been such as entirely to prevent the forma- 

 tion and separation of the sugar. The copper then 

 should be filled in the shortest possible space of 

 time ; hut if large masses are acted upon, and, 

 consequenth', large coppers made use ofj it is es- 

 sential, in order to charge them rapidly, that a 

 number of rasps and presses should be employed, 

 proportioned to the required despatch of the opera- 

 tion. Thus, to charge a boiler of between 500 and 

 600 gallons in two hours, which would be a rea- 

 sonable time enough, it wouM he necessary to rasp 

 and press, during this interval, about four tons of 

 roots. Supposing that a rasp is used which in 

 twelve hours will finish eight tons of roots; sup- 

 posing also a hj'draulic press which is capable of 

 working of 8S0 lbs. of pulp in one hour, it will re- 

 quire, in order to obtain -570 jTallons of juice in two 

 hours, three rasping mills and five presses ; but if 

 only this quantity is required to be obtained in 

 twelve hours, and, consequently, that there is hut 

 one delineating boiler, the three rasps and five 

 presses will only work two hours a day, and remain 

 idle the rest of the time. This is bad. On the 

 other hand, when it is attempted to fill a boiler of 

 570 gallons by means of only one rasp and one 

 press, the inconvenience will occur of delavintj the 

 juice before the process of defecation can be begun. 

 Both these evils ought to be avoided. 



A variety of reasons are given by JM. Dubrun- 

 faut, for preferring boilers of a medium size to 

 those of large dimensions. He consitlers those of 

 about 90 or 100 gallons as much more convenient 

 than the larger sizes belbre enumerated. Of course 

 two or more would be required, according to the 

 magnitude of the work. Two boilers of these di- 

 mensions would readily do the work of one of 570 

 gallons, and the first cost of them would not be 

 more. As soon as one is brought to the boiling 

 point, the fire can be removed to the "rate of the 

 other; in thort, whilst the luocess of deftjcaiiug is 



going on in the one, the other may be left to pre- 

 cipitate its extraneous substances. 



A defecating boiler, intended to act by precipita- 

 tion, ought to be equal m height to its diameter. 

 A fifth of the size absolutely required to contain 

 the juice slionld be allowed f()r boilinii; space : thus, 

 a boiler which would hold 100 gallons, ought to 

 be larire enoiiffh to boil one hundred and twenty 

 gallons in. The boiler oiiiiht to be mounted to such 

 a height as to allow of the li(|Uor running off clear, 

 by an easy slope into the evaporatinir boiler. The 

 femperatiu-e should never exceed 80^ of Reaumur 

 (212 "^ of Fahrenheit.) Thus, admittinir that the 

 boiler is 36 inches in height, and the same in di- 

 ameter, it should have a grate of about the follow- 

 ing j)roportions: — 



Length . 

 Breadth 



28 inches. 

 15 '• 



This grate is of cast iron and composed of 10 bars. 

 The bottom of the boiler is placed about 15 inches 

 idiove the grate, round which is a flue to enable 

 the flame to circulate to the height of the charge. 

 This flue, at its opening into the chimney may 

 Ibrm, in section, a parallelogram of 140 square in- 

 ches. A boiler on this construction presents to 

 ihe fire a surftice of 413 s(juare feet, and will bcal 

 its contents in about ihreequartersof an hour, with 

 the consumption of 24 lbs. of coal. If wood is 

 burned there must be double the quantity allowed. 



§. 2. j^ppendages to a Defecating Boiler. 



They are the following : — 



1. A thermotneter and an areometer. 



2. Scales and weights to weigh the lime. 



3. A bin for lime, and wooden pails or buckets. 



4. A measure either of lead or copper, for sul- 

 phuric acid. 



5. A wooden instrument to stir up the liquor in 

 the boiler. 



6. A platedspoon, to observe the juice with, and 

 an exf)eriment saucer. 



7. A skimmer. 



8. A filter and funnel. 



Areometer and TTiermometer. 



Beaume's areometer is generally allowed to be' 

 the best ; il should be provided with a tin case, 

 havino; a wooden handle. The liquor about to be 

 weijrlied is drawn up in this tin case, which is 

 held by the handle. It is important that the juice 

 should be examined always at the same tempera- 

 ture. It should be taken as it comes ti'om the 

 press, and plunged, by means of the fin case, in 

 water from a well or pump, so as to reduce it to a 

 temperature of 10° of Reaumur (55 ° of Fahren- 

 heit.) Then insert the areometer ; and if all sub- 

 sequent trials are made with the same precaution, 

 the comparative results will not fail to be correct. 

 In this state tlie juice varies from 5° to 10° (areo- 

 metriques) of'Beaume. If weighed when boiling, 

 a difference will he found of 4^^ more or less, be- 

 cause then, the heat expanding the liquid, dimin- 

 ishes the specific gravity of it. 



The areometer will also be found useful in the 

 evaporation of the juice, to e.stimate the precise 

 time fiivourable to clarification. Being of glass, 

 and consequently very liable to be broken in the' 



