1VAWS'S SUGAR - PLANTAR'S MANUAL. DESTRUCTION at certain epochs, to

be followed by replacement in order to advance, seems a law of the natural, the national, and the social world. The history of the earth as unfolded by geology exhibits this principle in

every stage of progress. History and tradition, or tradition's echoes, point t) the invasion of an inferior by a superior race, and the national destruc- tion or absorption of the former. Greece and Italy, under unknown or disputed colonists—Gaul, Spain, and Britain, under the Romans—are merely an illustration of the principle which is now at work among the aborigines of America and Australasia. It would be needless to point out bow social changes operate upon manners, and whole classes become ex- tinct as one grade advances upon another : where is now the feudal baron, or the courtier wit, or even " the fine old English gentleman" ? In looking at industrial occupations, the destruction of copyists to be re- placed by printers will at once recur to every mind. In the memory of us all, the " long stage" with its " characters " has nearly vanished from the land ; and other if less rapid and staring changes have already, taken place in various branches of industry, or are now in progress. It is possible that the entire English and Irish agriculturists must be re- placed ; probable that the West Indian planters must share the same fate. Whether this is to be accomplished by total ruin, or by absorption, or by a social change brought about by giving new ideas to the existing race, would be difficult to decide upon after the experiment, much more h priori.

To contribute something to the last alternative—to change measures rather than men—is the object of Dr. W. J. Evans in the Sugar- Planter's Manual. Dr. Evans fully admits the difficulties in which the planter is involved by partial free trade, which has destroyed his pro- tection without giving hint freedom of industry, by the want of labour under which he suffers, by the destruction of capital and the loss of profits which crude and popularity-hunting legislation entailed upon him, and the depression and lack of enterprise that such a state of' pres- sure produces in the mind. Still he thinks that something may be done by the introduction of agricultural machinery or implements, except in British Guiana, which, from " the nature of the country, is at present wholly dependent on manual labour." In his opinion, however, the prin- cipal means of safety are, first, greater attention to the quality of the cane' and the precise time of cutting it, so as to secure a richer quality and larger quantity of "juice " ; second, improvements in the manufacture, from the first "pressure" of the canes till the shipment of the sugar and molasses. This last section is indeed the subject of the book ; for the quality and treatment of the cane are rather generally suggested than specifically directed.

The Sugar-Planter's Manual consists of two leading divisions; the first relating to the physiology and chemistry of the sugar-cane, the second to the various processes of the sugar-manufacture. In the first part, Dr. Evans explains the structure and component parts of the cane in various stages of its growth ; and, by an analysis of its elements, shows how' readily sugar, through minute causes, may become glucose, (that is, the saccharine matter of fruits which never crystallizes,) or undergo other changes that injure the quality or lessen the quantity of the produce, er, cause increased expense in extracting it. Hence he adduces the rules he. lays down as to judgement in the choice of the plant and the time oft. cutting, the rapidity with which it should be conveyed to the mill for crushing lest decomposition should ensue, and the advantage of draining where the soil requires it and the means of the proprietor permit it. hd a literary point of view; this part is perhaps too elaborated, by evolving too minutely the principles of botanical chemistry, and an arrangement which. has the effect of repetition ; but it is well adapted for acquiring a thorough knowledge of the physiology and properties of the sugar-cane.

The practical application of botanical and manufacturing chemistry to the production of sugar is the subject of the second division ; and it forms, we think, the most useful part of Dr. Evans's work. The Doctor himself appears to be practically acquainted with the processes as conducted in several sugar-growing colonies ; he has carefully studied the various contributions of foreign chemists to the science, or the business of sugar-manufacture, especially from the beet-root ; and he has gleaned some floating knowledge upon the subject from those colonies in which he has not been. He possesses a great quality for a practical improver—a sensible mind. He draws a distinction between chemical and commercial production—between that which is beat and that which under the cir- cumstances can best be done. Many processes, available to the refiner amidst the skilled labour and dense manufacturing population of Europe, are beyond the power of the planter, or could not in his circum- stances be profitably applied. As the subject is of great importance to the West Indian proprietor and the public at large, it may not be useless to give a general idea of the sugar-manufacture, so far as to make Dr. Evans's views intelligible.

Healthy cane in a state of maturity is shown by chemical experiment to consist of 90 parts of fluid and 10 of solid matters ; the fluid constituting what is called cane-juice, the solid consisting of woody fibre. The quan- tity of sugar in the juice has been variously estimated ; indeed, indepen- dently of accidental circumstances, it must differ with the quality of the cane. Dr. Evans takes the silent. at 18 per cent of the fluid, but considers that it not unfrequently exceeds 22 per cent. To extract it all is possible to the chemist in his laboratory, but impossible for the planter: or if it could be done, the expenses would absorb the profit. Our author, however, considers that a much larger amount may be obtained than is now done; and the chief end of The Sugar-Planter's Manual is to point out the way.

When the cane is cat, the first operation is to carry it to the mill, where it is crushed by means of rollers in order to extract the juice. There are no regular statistics of the average amount of cane-juice practi- cally extracted ; it must vary with the efficiency of the mills and the motive power: but instead of 90 parts, the highest estimated average is only between 50 and 60 per cent. M. Duprez, who was sent by the French Government to Guadeloupe to make experiments, could only ex- tract from the mills in that island 68.5 per cent at the highest, and his average was only 56 per cent. Other calculators give a lower amount for other places. Dr. Evans says-- " The lowest amount that my own observation, in the West Indies, permits me togive, is 47 per cent, and the highest 61 per cent : but, as I have just mentioned, it has been too limited to be offered as an authority. In the island of Madeira, I obtained at two different times by the same mill, and from canes of similar charac- ter and quality, 47.5 and 70 2 per cent ofjnice. The mill was a small one, made at Aberdeen about two years previously, on the ordinary principle, with horizontal rollers; and the motive power was cattle. During the experiment which fur- nished the last and largest result, the rollers were braced more than usually tight, and the number of canes introduced at a time were tire or six, being the utmost that the strength of the cattle would admit of The canes were squeezed once only; indeed, the megass was too much lacerated to admit of its being passed between the rollers a second time with advantage."

Dr. Evans therefore concludes, that a much larger quantity of cane- juice could be produced than is now obtained, by increasing the motive power of the mills, and by a better system of managing them, as well as by treating the canes when in a certain condition. " By following the foregoing rules, the quantity of cane-juice may be increased at least'20 per cent; that is, a mill which ordinarily gives 50 lbs. of juice for every 100 Is. of canes which are crushed by it, may by a little attention be made to in- crease the quantity to 60 lbs. at least, and the one which now produces 60 lbs. may be made to yield 70 lbs. from a like quantity.

"This amelioration may be obtained without any additional outlay of money; a little watchfulness on the part of the planter, to see that his orders are carried out, being all that is required for its accomplishment.

" There are, unfortunately, many mills, which, either from age, the want of so- lidity originally, or from a construction altogether imperfect, produce even an in- ferior result to those given above. A comparative amelioration will follow the ap- plication of these rules in all cases; but the only real amelioration which can be effected in the cases alluded to, is the removal of the old mill and the erection of a new one. The .present, it is true, are not the times when sugar properties in the West Indies permit an indiscriminate outlay of capital for the purchase of new machinery. But it must be remembered, that the difference between 45 or 50 .lbs. and 70 lbs. of juice, extracted from equal quantities of canes, indicates a corre- sponding difference in the amount of the crop; while the annual expense attend- ing the cultivation of the estate would be in both cases the same."

There lurks, however, in the planter's mind, a reason for not extract- ing all the juice which he can, and very probably he may urge it in formal argument : the refuse of the canes, or megrim as it is called, is his fuel, by which the succeeding crop of sugar is prepared. If, therefore, he increases his quantity of juice, he lessens his stock of fuel. To this Dr. Evans replies, that natural changes deprive him of much of the com- bustive matter in the megass ; and that were it not so, it would be cheaper to make more sugar and buy fuel. " It is found in practice impossible to dry the megass in such a manner as to preserve within it the quantity of combustible materials given above. For whe- ther it be stacked at once, or be preyiously exposed for some hours to the rays of the sun, fermentation of the juice retained in it commences, and the sugar ie con- verted into incombustible bodies, as gum; •lactic acid, &e., or into others which are rapidly evolved, as carbonic acid and alcohol; so that when the time arrives when its use as fuel is required, little more remains available for the purpose than the woody fibre: that is to say, that instead of obtaining 17i of fuel from canes which have given 50 parts in 100 of juice, 10 parts only are actually serviceable; and the amount of evaporation which could be effected by this quantity would be equal to 50 lbs. of water only. " The planter would appear to be in a great measure aware of this fact, by offering as a mason for the imperfect pressure to which he submits the canes, the fear of having a larger evaporation to effect than his fuel is capable of accom- plishing. When he states, however, that by imperfect pressure he is thereby ob- taining a proportionately increased supply of fuel for the following year, he is manifestly in error; for the only constituent of the cane on which he can rely for that purpose is the woody fibre, which will be equally abundant to whatever ex- tent the pressure may have been carried. "To exemplify the loss which a sugar plantation annually sustains from an adherence to this most shamefully extravagant system, I will suppose, that by increased pressure the amount of cane-juice obtained is augmented merely from 50 lbs. to 60 lbs. in every 100 lbs. of canes. It is clear that the amount of sugar, molasses, and rum, must be increased in the same proportion; and, therefore, an estate which otherwise would give 200 tons as its annual product of sugar, would from this cause alone afford 240 tons.

" Let us also suppose, that there being no other available fuel at hand in place of the megass, coals have to be imported from England at an expense of 1/. per ton, and that 240 tons would be required to evaporate the requisite quantity of cane-juice to make the same number of tone of sugar: the price of the coals would represent the expense attending the augmentation of the produce. The sugar would be worth at least 201. per ton; consequently the clear gain would be 8001. less 2401, or 5601.

" The profit, however, would not be confined to the mere increase of 40 tons of sugar: the megass, after due fermentation, would produce an amount of farm yard manure, which, when thrown upon the land, would augment the quantity of canes for the ensuing crop at least 20 per cent, and in the greater number of colonies very much more. In Barbadoes, for instance, there are many estates that after a good supply of manure readily yield, in favourable seasons, three tons of sugar per acre, which without that assistance would not yield one."

The cane juice, whatever may be the percentage extracted, holds in solution other substances besides sugar. These are not large in point of quantity, but important from their effects. Some of these particles are Saline, which art cannot remove : they must be prevented, by acting upon the soil in which the cane grows. The other substances are three- fold,—insoluble impurities, such as earthy matter, pieces of cane, &c.; the preteine compounds, albumen, caseine; and soluble colouring matter. These are got rid of partly by mechanical means, and partly by the appli- cation of heat and the use of clarifying substances. The first process, which is called clarifying, is followed by evaporation ; whose object is, by means of heat to drive off some of the watery particles, till the cane-juice is concentrated into the consistency of a syrup of a certain degree of density. After this syrup has undergone treatments according to the evils to be remedied, it is fitted for crystallization; a process which it performs of itself while in the act of cooling, though it requires some mechanical assistance. The crystals form the common brown sugar of commerce; the viscid part which drains away is the molasses; and then the sugar-manufacture under the present system terminates. An account is given in detail of all these processes; and Dr. Evans enters at length into various modes of improving them, either with the existing means or by new methods. He also discusses the different dis- coveries that have -lately been made on the Continent or in this country in relation to the sugar manufacture, and considers how far they may be applicable to our colonies. These points will all have much interest for

the sugar-planter, even when he may be already acquainted with some of them: but we have said enough to indicate the scope and character of the work. And the latter suggestions of Dr. Evans are rather distin- guished for cumulative effect than for the large promise which he holds forth by improved modes of crushing the canes. The recommendation to reboil the molasses is perhaps of the most striking character.

" By the mode at present pursued of potting in the hogshead, the drainage as it escapes passes directly into the molasses' cistern, a cavity situated immediately beneath the beams of the curing-house. This cistern is consequently exposed and open. It is lined with cement, and is seldom in a perfect state of repair.

" Here the molasses remain until they are shipped, or until they are required for distillation. The result is, as might be expected, rats, cockroaches, arid other vermin, creep in and assist by their decomposition the rapidity and degree of the fermentation which under any circumstances is sooner or later certain to arise.

" In the palmy days of West India prosperity, this lax and improper system may in some degree have been excusable, owing to the highly remunerative prices obtained for all the produce: at present it can only be considered as one of extra- vagance, and therefore of loss.

• In the first place, a quantity of molasses is always lost, either in consequence of the leakage of the cistern, or from its absorption by the cement. 2. Owing to the evaporation constantly going on, a quantity of a soft, whitish, and amorphous sugar, is precipitated to the bottom of the cistern. 3. The vinous and acetous fermentation set in; and a part of the saccharine matter is converted into carbonic acid, alcohol, and acetic acid or vinegar, while another part is converted into un- crystallizable glucose. Thus, from a fluid possessing a bland. sweet, and sugary taste, the molasses are often changed into one having an offensive smell and a foreign and disagreeable taste. During the voyage these changes continue, and often increase in intensity, from the high temperature existing in the hold of the ship. Nevertheless, in spite of all the injuries which they have received, the molasses, on their arrival in this country, find a market, and by the skill of tha purchaser are converted into sugar of a quality superior to that from which they were originally obtained. "Can there be a greater proof of the ruinous management of a West India sugar estate than this fact? (In Jamaica, owing to the high price obtained for the ruin, the molasses are wholly converted into that spirit, and the loss is con- siderably diminished in consequence; but in those colonies from which molasses are exported, the decomposition which they undergo is a serious item in the de predation of revenue of every estate.)" Since Dr. Evans fully admits the evils under which the West Indian labours from a depressing legislation, his last remark' bears rather hard upon the planter. It is but a few years since refined or indeed improved processes were entirely forbidden to him, in order to protect the sugar- refiner at home. A duty of 8/. 8s. the hundredweight was imposed upon what is popularly called " lump " sugar ; duties of varying amount,' but higher than the article could fetch in the market, were placed upon any intermediate produce; and, in short, brown sugar (musrovade) was anb forced upon the planter by act of Parliament. From the time when ins Whig Ministry began their career of West Indian impolicy by the Ap- prentice Bill, to the moment of their deathbed Corn, Timber, and Sugar Budget, theseevils remained unmitigated ; Sir Robert Peel left them un-. touched in his great reform of the Tariff; and though some modification of the restrictions which fetter the sugar-grower have latterly taken place, very many still remain to encumber the free action of the planter.