54 Proceedings of Public Sociefies. 



The instant tlie liquor bcf^ins lo bnil, 

 sulphuric acid, dihilcd with twenty 

 parts of water, is poiircd into it, in the 

 proportion of a tenth part of tiic lime 

 employed; the whole innst be well 

 gtirred, that it may be complftcly mix- 

 ed : in order to ascertain tliat there is no 

 excess of lime or of acid in the liijuor, 

 it may be tried iipoii paj>er colonrcd 

 with turnsoi or cnrcnni!!. It is best to 

 suffer the excess of lime to remain, and 

 to employ no more of the acid, the mo- 

 ment that it gives to ihe curcuma paper 

 a tint of a pale tirick or deep w hite-wine 

 colour. After this operation, three jjcr 

 emit, of animal ciiarcoai, well pounded 

 to an impalpable powder, is mixed w ith 

 tlie liquor, and immediately afterwards 

 is added half of the charcoal that was 

 used the evening before. 



After the last addition of charcoal the 

 liquid is evaporated, till it has acquired 

 the consistence of from 18 to 20 de- 

 grees; it is then made to run into a 

 smaller and deeper boiler, and is lei't at 

 rest till the next day, when the boiling 



of tiie syrup is effected. 



T/te BcAlins; and Kefinin;^. — Tlic fjie- 

 ration of boiling the syrup is the most 

 delicate of any, but it has been rendered 

 extremely easy l>y the improvements 

 that have taken place in the jjreparatory 

 operations, especially since the use of 

 animal charcoal has been introduced. 

 TVIany manufacturers have failed in 

 boiling the syrup; and t!iat which sliou'd 

 be attributed to a bad manipulation, 

 has generally been supposed to be ow- 

 ing sometimes to the non-existence of 

 sugar in the beet, and sometimes to the 

 almost insurmountable .lifiioulty of ex- 

 tracting it. Now, tills operation is be- 

 come so easy tliat skim rises; it never 

 burns during thy boiling, and rc()uire:< 

 very little more care on the part of the 

 workman v.ho conducts it. Previous 

 to the boiling, the couccntrated juice 

 •niado the evening before, and which 

 still retains some tiegree of heat, is fil- 

 tered through a coarse piece of woollen 

 cloth ; it is then poured into a round 

 boiler, two feet in diameter and eighteen 

 inches deep, till it is one-third full, and 

 is then heated to ebullition, which is 

 kept up to the end of the o))(Mation. If 

 it chance to burn, it 'a perceived by puffs 

 of white smoke, which come f»)m the 

 bottom of the boiler, and burst through 

 the surface of the li(|uid, spreading a 

 pungent smell ; the fire nuist lie slack- 

 ened, the liquor .stirred, and the opera- 

 tion more carefully attended to. The 

 means of judging tliat the operation is 



[Aug. 1, 



going on well arc, when it boils dry and 

 with noise; v\hen the syrup detacher 

 itself from the skimmer without drawing 

 into threads, and without adhesion; 

 when on striking the boiling mass with 

 the back of the skimmer, the blow 

 sounds dry, as if it struck upon silk; 

 when it produces very little skim ; when, 

 on taking up some of the froth, or the 

 bubbles out of the boil, with the skim- 

 mer, the bubbles disajjpear directly and 

 resolve irito liquid : this latter character 

 distinguishes the bubbles of the boil 

 from those of the skim; and, lastly, we 

 may be satisfied that the operation has 

 proceeded well, if no traces of black 

 can be perceived at the bottom of the 

 boilc!-, mid the surface appears clean. 



Tiic time proper to terminate the boil- 

 ing of tlie syrup may be known by 

 woiking a drop between the forc-Cngor 

 and thumb, till it has acquired the tem- 

 perature of the skin, and separating the 

 linger and thumb rapidly : when it be- 

 gins to form a thread the operation is 

 far advanced, and the experiment must 



be fieqnently repeated. The boiling 

 nmst be discontinued the moment that 

 the thread breaks dry. As soon as it is 

 ascertained that the operation of boiling 

 the syrup is eomplete<l, the fire is smo- 

 thered, and a few minutes afterwards it 

 is poured into the cooler, taking care to 

 j)our it high, that it may be mLxed with 

 air, for it is observed that this facilitates 

 the crystallization. 



In the evening, wlien the whole is 

 collected in the cooler, Wxc forms which 

 are denominated hastardcs are filled ; the 

 crystallization of the sugar immediately 

 begins, and is almost always complete 

 the next day; so that, in 24 or 48 hours 

 after, it is put into the forms; these forms 

 may, without ineonveinenee, be placed 

 upon the pots for tlie melasscs to run 

 out. 



To refine with alcoliol, the operation 

 must be commenced immediately as the 

 melasscs begins to run ; for if any time 

 is allowed for the sugar to dry, the me- 

 lasscs which moistens the crystals thick- 

 ens, and forms a very hard coat upon 

 the surface of the sugar, which tlie al- 

 cohol detaches with great difliculty: 

 accordingly, the moment that the me- 

 lasscs begins to run, the surface of the 

 sugar-loaf contained it! the form is to bo 

 serapetf, and a litre of alcohol at 36 

 degrees of commerce, poured by degrees 

 over tiie v\ hole surface, the little orifice 

 of the form being stopped; the base of 

 the form is then carefully covered to 

 prevent tiie evaporation of the alcohol. 



