158 



should be short, and sheltered from the suu's rays, they having the 

 effect of greatly expediting chemical action. 



I shall say no more on this subject, but will proceed to consider 

 the mode of tempering and clarifying cane juice, and the action of 

 lime on the various substances contained therein. The expression 

 "tempering" has, I presume, been adopted in consequence of the 

 use of tempered lime for the purpose of precipitating the feculen- 

 cies, held in solution in the cane juice, into a state of suspension ; 

 and clarification is the process by which we afterwards clear the 

 liquor of these and other foreign matter. Now, as I before ob- 

 served, " fermentation should be most strictly guarded against 

 our first eff'orts should be directed to free the cane juice from those 

 substances most conducive to that process ; and on inquiry we find 

 these to be albumen and gluten ; so far, however, from getting rid 

 of them in cold tempering, we adopt a course which retains them 

 permanently in solution, as lime has the power of rendering them 

 permanently soluble, and of forming soapy compounds with resin, 

 wax, and chlorophyle, or the green coloring matter of leaves, form- 

 ing an insoluble compound with and precipitating only the starch, 

 and converting at the same time the green color of the chlorophyle 

 (which is, in all probabiHty, attached to the resin), into a dark 

 brown, of a greater or less intensity, according to the composition 

 of the cane juice, and, consequently, the quantity of lime required ; 

 it follows, therefore, as a matter of course, that if juice be tempered 

 before these substances have been removed, they must be perma- 

 nently retained, and they have all the power of preventing granu- 

 lation. 



Albumen and gluten are both coagulable by heat ; if, therefore, 

 we raise the liquor to the boiling point prior to applying the lime, 

 taking care to remove the scum as soon as it shows signs of break- 

 ing, and continuing the boiling imtil the scum thrown to the 

 surface becomes inconsiderable, we shall find that the albumen and 

 gluten, in coagulating and rising, have carried with them the small 

 particles of woody fibre, the wax, and a large proportion of the 

 coloring matter, and that the lime will now throw down the starch, 

 and any other little impurities remaining in suspension in the 

 liquor, leaving it perfectly clear and bright. Tempering is an 

 exceedingly delicate chemical operation, and I have no hesitation in 

 saying, that on its proper performance depends the quality of the 

 produce. The following simple experiments, which all have it in 

 their power to try, will, if they give themselves the trouble, fully 

 satisfy them of two important points — the superiority of the hot 

 over the cold mode, and the necessity for great attention to the 

 operation of tempering. Let them take a tumbler of cane-juice and 

 a bottle containing lime water, add the latter to the former by 

 drops, pausing and stirring between each, and they will find that, 

 after the addition of a certain quantity, the opaque gummy 

 appearance of the liquor undergoes a change, and the impurities 

 contained in it separate into flakes, which increase in size with 



