1837] 



F A R M E R S ' RE (I I S T E R . 



89 



fskewer, dipped into a bottle of the pyrup. It will 

 be as wi'll, also, to iiave on this saucor a piiiall 

 (luantity of well prepared blue tiirnsol. This 

 done, he tlu'n may proceed to examine the juice. 



The thick scum is first removed, which has 

 been produced by the lime and sulphuric acid, a 

 quantity ofthe puriiied juice is then taken in the 

 e])oon, to see ifthe clearness and precipitation <;o on 

 well, provinfj, in that case, that the siil[)huric ticid 

 has not been over-applied. The heller to assure 

 (vne's self oflhis.leta wooden peffbe dipped in the 

 juice contained in the spoon, which mix with one 

 of the drops of gyrup of violet in the saucer. If 

 the alkali is predominant in the juice, the syrup of 

 violets will chant',p. to a fine deep green color, in 

 proportion as the alkali becomes weaker, the ijreen 

 wdl take the more time to develop itselt'. and will 

 lose its deep hue. The addition of the acid must 

 cease when the syrup, touched by the juice, turns 

 but slowly to green. A certain number of drops 

 of syrup have been recommended to be placed in 

 the saucer, for the convenience of making seve- 

 ral dhlerent experiments. It will not be amiss, 

 alier ascertaining l>y the syrup ol' violets that 

 the proportion ot' acid is sutficient, to touch the 

 spots of turnsol with the juice, in order to be satis- 

 fied that It will not turn them red; for it is the pro- 

 perty of acids to change the blue color of the turn- 

 Bol to red. This latter experiment is of no other 

 use than to prove to an inexperieneed practitioner 

 that his eye has not deceived him in the tbrmer 

 experiment, [f too much acid, it must not only 

 be neutralized by the lime, but there must be also 

 a slight excess of this alkali. Care should be taken 

 in the above trials, that the quantities of juice and 

 syrup should be eciual, or nearly so. lor if either 

 predominate, the results will neither be satisfacto- 

 ry nor correct. 



When it is ascertained that the boiler contains 

 but a slight excess of alkali, and after the contents 

 have been well stirred, the fire is withdrawn, and 

 ihey are left to settle. 



In about half an hour the liquor will be clear 

 enough to draw off- One may reckon that 114 

 gallons of juic^, requiring 6 or 7 lbs. of lime, will 

 take nearly a kilogramme (35 oz. av.) of acid to 

 neutralize them sufficiently. Admitting that it 

 requires the amount of two charges of the press 

 to fill one boiler, from a quarter to a third of the 

 Aveight of lime required for a defecation may be 

 added to the juice, in tne vessel in which it comes 

 from the first pre ss. This measure will be parti- 

 cularly advisable when the temperature oi' the 

 place "be at from 61" to 73° of Fahrenheit. 



Third Method— M. Adiard's Plan. 



Achard. when he established his manufactory, 

 was indebted to no one, either for plans or machi- 

 nery, but struck out a path for himeellj in which 

 he has, to a certain extent, been eminently suc- 

 cessful. His method of defecation difi'ers from 

 those we have been describing, inasmuch as, in- 

 stead of using the lime first, and then the sulphu- 

 ric acid, he begins with the latter, and neutralizes 

 with the former. It differs also in other respects, 

 which will be hereafter alluded to. 



The juice, on first issuiug irom the press, was 

 deposited in lame earthen vessels, wdiere it was 

 acidulated. This acidulation was obtained by l-;f 

 drachms (avoird.), 2.^ grammes of sulphuric acid 



foi every litre (61 English cubic inches, nearly 

 two pinis) of juice, not more than six or sevpn 

 hours elapsing between the extraction of the juice 

 and its acidulation. 



The l()llowing is ]\1. Achard's own account of 

 the process adopted by him. ''The boiler having 

 been well cleaned, the botsom is unilbrmly cover- 

 ed Avith chalk, finely powdered, in the proportion 

 of about three drachtus (i)r every litre (61 cubic 

 inches) of juice, acidilied the day before.* It is 

 then about tu'O-thirds filled, that there may be 

 room for the scum to li)rm on its surface. The 

 contents of the several earthen vessels are then 

 got together, and poured into the boiler. The up- 

 per part of the acidified sugar is clear, but the bot- 

 tom is thick, of a greyish color, from the flakes' of 

 albumen acd other impurities precipitated by the 

 acid. The sugar is well mixed with the chalk, 

 in order that the combination may be complete; 

 ibr the object of tliis operation is to saturate the 

 sulphuric acid which has been added to the su- 

 gar. It thus forms a sulphate of lime which is 

 deposited at the bottom of the boiler. This preci- 

 pitation is attributable to the insolubility of the 

 lime, which requires 2-50 or 3C0t times its weight 

 of water to hold it in solution. Such of it as re- 

 mains in the sugar is separated by an alter pro- 

 cess. 



• '-It would at first appear, that any sort of calca- 

 reous earlh may be employed tor this purpose; but 

 experience proves the conirary. The true reason 

 of this is, perhaps, that these calcareous stones 

 are always mixed with extraneous substances, in- 

 somuch that their weifiht does not exactly indicate 

 that of the calcareous carbonate; to say notliing 

 of the obstacles which these substances interpose 

 in the way of the clarification. By the combina- 

 tion of the sulphuric acid with the lime, the car- 

 bonic acid with which it is saturated is set at liber- 

 Xy and remains in the juice, sometimes showing 

 itself in litlle bubbles. Experience has proved the 

 necessitv of disensrairing this acid beibre refining, 

 because the extraction of the suirar is thereby \'a- 

 ciiitated. The best means of eHecting this, is by 

 adding chalk converted into quicklime by the ac- 

 tion of fire. If burnt belbrehand, it should be 

 carefully preserved from the elFect of the atmos- 

 phere. The calcined chalk :;iay be added to the 

 juice in the boiler about a quarier of an hour after 

 the unburnt chalk, at the rate of two drachms 

 avoirdupois lor every gallon of juice; the boiler is 

 then covered, and the ihermometer placed in it. 

 When at 100° the cover is half taken ofl^, and 

 skimmed milk is added at the rate of 10 or 14 litres 

 (2 to 3 ffallons) per 1000 litres (227 gallons) of 

 juice. The whole is well stirred, and then covered 

 down. When the thermometer is at 79° (210°) 

 the fire is extinguished, and when the temperature 

 drops to 145° oi~ 165°, tlie boiler is uncovered. Be- 

 ibre the clarification, the albumen separaied frons 



* Observe, the juice is never put into tiie boiler till 

 it has been in contact wiih the sulphuric acid about 

 twenty -four hours. 



fM. Achard states 470 times its weiijht of water; but 

 we are assured by M. Uubrniifaiit, that in beet-root 

 juice it is much more soluble than in water, and that 

 even in this latter it only requires 250 or .300 times its 

 own weio-ht to dissolve it. 



