1837] 



F A R M E R S' REGISTER. 



401 



still inltniiteil ot'improvt moiifs. lie tlicielbrc pro- 

 poses the lollowiii;! ;is his own : — 



6. Plan, of Concentration. 



ft has received the sanction of expenencp, and 

 will he ()iiriicul;)rly advanlaixeou.-? in lar<re concerns: 

 three hoilers are su[)posed to he nec(>ssary. each 

 alibriliiio; a chanre of 500 litres (114 irallons) eve- 

 ry iialf hoiu-, malting 24,000 litres, or 5472 gallons 

 in the 24 hours. 



The author has ascertained that the syrup, to 

 underiro a suitable evaporation, ouijht never to 

 present in the boilers a laver reduced to more than 

 5 centimetres (2 inches) in depth. This is the 

 minimum of reduction to which it can he hroufrht 

 without danirer ; Ibr beyond that, the ebullition will 

 not operate well. 



It is well known that to produce the greatest 

 evaporatiniT etfect, the puce outrht to be spread 

 over the larirest possible surliice, 'but that this nnist 

 necessarily be limiieil by the reduction in bulk 

 which the juice will under<ro in concentration. 

 The inconvenience arisinsf therefrom is overcome 

 in the lollowiuii; manner. First, the piice is so dis- 

 tributed over the suriace as not lo complete its 

 evaporation there; but when the layer shall be re- 

 duced to 5 centimetres (2 inches,) this same juice 

 is removed to a vessel present ini; a smaller surface, 

 and where, consequently, it undergoes a new evap- 

 oration; then, when on this new suriace it shall 

 again be reduced to 5 centimetres (2 inches,") it is 

 removed to anoiher still smaller, and so on. How- 

 ever, three of these removals have been found to 

 be sufficient, in the progress of which the juice 

 has been exposed lo the action of the fire but an 

 hour and a half 



It will be well to asc<^rlain the quantity of water 

 evaporated fi-om a given quantity, say 500 litres 

 (114 gallons) of juice, the mean richness of which 

 is 6 areometrical decrees, and which by concentra- 

 tion is raised in density to 30 degrees when cold. 

 A calculation is then given, by which it appears 

 that these 114 gallons will be reduced to 18| gal- 

 ions (82 litres,) 9 gallons of which are water. 

 There must then have been evaporated durinnr the 

 concentration 95^- ijallons = 919 lbs. of water. 



In adoptinir vessels of three different calibres to 

 effect the coticentrat.ion of 500 litres (114 irallons) 

 of juice, antl the coiisecjuent evaporation of 95.^- 

 gallons of water in half an hour, it has been taken 

 lor granted that the boilers were worked simulta- 

 neously and continually. It would, of course, be 

 necessary in such case, that they should be dis- 

 charg 'd and recharired every half hour. But in 

 ordf^r to do this properly, their evaporatino; sur- 

 faces should be exacilv proportioned to the quan- 

 tities of liquid received by each of them, and to 

 the effect which they are intended to produce. 

 Thus the first (500 litres) ought to have an evap- 

 orating surface equal to 861 square feet. The 

 juice will be distributed over abed of 10 centime- 

 tres (4 inches) in depth, and as it ouaht not to con- 

 tinue in a state of ebullition more than half an 

 hour, after this time it will have lost half its bulk 

 of water, and will thus be reduced to 5 centimetres 

 (2 inches) in depth. The juice will then be trans- 

 ferred into a second boiler, the surface of which 

 will be equal to 430 square feet. From thence it 

 will be removed to a bed 4 inches deep, as in the 

 first instance, and after evaporatinn; half an hour 

 this will also be reduced to 5 centimetres, losing in 

 Vol. V-ol 



the above lime. 275lbs. of water. There then re^ 

 main 2S (gallons of syrup, which will be taken to 

 a third boiler, presenting a surfice of 215 square 

 feet. This last vessel wii'l be cajjahle of evapora- 

 ting 14<ralloiis in half an hour, making a total of 

 437 litres (100 trallons) of water eva[)orated, 

 whereas only 95;} iialloiis were wanted. II" the 

 size ol these vesseU be ob|ecied to, it is very easy 

 to provide aL'";nnst this evil; l()r instance, instead 

 of one boiliM- of ^^OO superficial feet, one miij;ht em- 

 ploy l()ur of 215 leet, and in place of No. 2, which 

 is said lo contain 430 square Ihel, two of 215, and 

 so on. 



§ 2. Oftfioj^ppendagestothe Evaporating Vessels 



The walls of the fiirnacee ou<rht to be stronirly 

 built, and protecied on their u|)per edges by sheet 

 co|)per. 



A skimmer is wanted (breach boiler, proportion- 

 ed to their resjiective sizes, and also some good 

 areometers, to indicate in a constant and uniform 

 manner the point of concentration. Each evapo- 

 rating boiler should have a wooden orearthern ves- 

 sel to receive the skimmings, which are removed 

 during the process of" concentration. 



§ 3. Process of Concentralioii. 



The apjiaratus f()r this purpose, it has already 

 been stated, should be so placed that the clour 

 juice from the defl^cation f)oiler should be deliver- 

 ed to it by a natural declivity, with a view to 

 economy of labor. 



The process of" concenirafion is extremely sim- 

 ple, except, perhaps, in the evaporaiing' battery, 

 (^batlerie evajyoratoire) wh'n:h will be described by 

 and bv ; in the meantime there are some partic- 

 ulars relatinfr to the management of the syrup 

 common to all methods, and these are as follow : — 

 When the piice leaves the defecating for the 

 concentratiniT iioiler, it irenerallv froths a good deal; 

 but this frolh is oflen occasioned simply by the fall 

 of the juice in the air. However-, if"this froth, in- 

 stead of subsiding immediately, have a sort of con- 

 sistence — if lilt and iireasy to the touch, it would 

 be a certain proof that the juice had been badly 

 defecated. In the defecation boiler, the juice often 

 fidls, when left to settle, from a temperature of 80"^ 

 Reaumur (212^ Fahrenheit) lo 50 or 60=^ R. (145 

 or 167" F.,) esfieciall}^ when a lartre quantity is 

 operated upon. Tl will be well therefore to prolong 

 this period of settlement Ibr two hours. The juice 

 in that case will never enter the concentration boil- 

 er in a state of ebullition, and beflire boiling, it is 

 covered wilh a white scum, the formation of which 

 it is advisable to encourage bv not forcing the fire 

 too much at the outset. This scum is composed 

 of albuminous matter, which, coaixulatinir, thus 

 I envelopes all the panicles held ih solution in the 

 ! liquid, and carries them to the surfitce with it. It 

 is generally white, but grey when the juice has 

 not run perfectly clear, a circumstance that now 

 and then will occur, even with the most experi- 

 enced hands. In this case a little blood, or white 

 ofeo-cT, issorifietimes applied with eff'ect to the juice. 

 The scum will then rise more abundantly; but 

 care must be taken so to manage the fire as that 

 the boiling shall only he visible on a point of" the 

 surface, and that very gently, oihervvise the scum 

 will mix again with the liquid, and in that case 

 can only begot rid of by filtration or precipitation, 

 both of whicli, on every account, ought to he, sed- 



