§ 4. Operation of Boiling. When the clear syrup is collected in the reservoir in sufficient quantity for a boiling, which, in a continued work, may be about 200 or 300 litres (45 or 67 gallons), this operation is proceeded with. The boiling pans are charged with 41 litres (9 gallons) of syrup each. The fire is then applied to the furnace, and the thermometer suspended. The syrup is soon in a state of ebullition; for it is nearly at the boiling point from the filters. If by any chance the syrup in the reservoir should be at all troubled, the white of an egg may be applied to each charge of the pan, and then carefully skimmed. When the syrup is good, it gives out, after having thrown up its first scum, a white pearly froth, which covers the surface, and ought to remain all the time of boiling, only that it should turn brown towards the end. There are always, during the boiling, some moments in which the syrup rises, and threatens to overflow the pan. To hinder this, small lumps of butter are occasionally put into the syrup. The workman who is charged with the management of the fires ought to watch the thermometer, as the period for proving the syrup advances. When, for instance, it is at 89°, proof should be taken. At 89° or 90° it is time to discharge the pan. The proof point of molasses, when reboiled, is generally 91° or 92° R. When the boiling is finished, the pan should be discharged. This may be done immediately into the cooler (rafraichissoir), or into some intermediate vessel adequate to receive such a charge. Two charges of 41 litres (9 gallons) each, will give about 11 gallons of boiled syrup. CHAP. X. Cooling of the Boiled Syrup. When poured out of the boiling pan, the syrup is put into a vessel capable of holding all the boilings furnished during 10 or 12 hours. In its progress thither, the syrup undergoes two movements, and two airings, by the mere pouring from the pan into an intermediate vessel, then from this latter into the cooler. When the syrup is thus got together in the cooler, it remains there 10 or 12 hours before it is run into moulds. It ought to NEW SERIES, VOL. I, NO. I. D fall during this time to 65° or 70° R. (180 to 190 F). It then is time to run it into moulds. If the syrup is good, one ought to find many crystals at the sides and bottom of the cooler. These crystals, distributed throughout the liquid mass, are carried into the moulds, and the syrup thus undergoes a new airing and a new movement, which assist the crystallization. It is necessary to be careful not to suffer the syrup to be carried at too low a temperature into the moulds. § 1. Cooler and its Appendages. The cooling pan (rafraîchissoir) is a sort of moveable copper, only that instead of heating, it serves to cool the syrup. There is, of course, no fire-place attached. It ought to be of solid copper, round, and rather wider than it is high. The size ought to be proportioned to the quantity of syrup that can be boiled in 12 hours' work. With the evaporating battery of seven boilers and two bascules, one should be able, in 12 hours, to obtain 1176 litres (265 gallons) of boiled syrup, and with the small battery, in the same time, 132 gallons. În the first case, therefore, the cooling pan should be capable of containing 14 or 1500 litres (340 gallons or so), and in the second half that quantity, or 170 gallons. Height. It will be well to have two or three of these pans. A sort of spatula (of iron) is used with the above, which serves to detach the grain. It should be about 4 feet long. Also, two filling pans or basins. These basins are of copper. There ought to be a ladle or large spoon, (also of copper), and a thermometer to each pan. § 2. Operation of the Cooler. When the first boiling is discharged, it would very soon cool were not a second soon added, a third, and so on, in succession. When two boilers are used, the charges are supposed to come every quarter of an hour, whereas if only one is used, the interval between these will be half an hour. Experience has shown that the most suitable temperature for filling the pans is from 60° to 70° R. (167 to 190 F). The boiled syrup should remain 10 or 12 hours in the pan, provided that the temperature does not fall below 60°; to prevent which, it may be advisable, besides a lid, to cover the sides with flannel, which preserves it from contact with the air. In case these precautions should fail of preventing the pan from cooling too fast, it can be charged every 6 or 8 hours; by which means, though it would not be full, yet this is a matter of no great consequence. In any case, it will be advisable, every four or five charges, to stir up the mass with the iron spatula. CHAP. XI. Filling the Moulds. The operation of filling the moulds consists in pouring the syrup into certain vessels, where it is intended to crystallize. This immediately follows that of the cooling pan (rafraichissoir); but before we proceed to filling them, it may be as well to say something of the moulds themselves. § 1. Moulds. These are principally of common earthenware. Those most commonly in use for beet-root sugar are of the largest size, and are known by the name of bastards. They will hold from 10 to 12 gallons each. They are cone-shaped, and have a hole at the bottom of them. Each mould should have a pot, made of burned clay, placed underneath the point of the cone, (as will be hereafter explained), to receive the molasses which drains from it. A mould of this kind, full of well-boiled syrup, will purge itself of molasses in a month. Thus the number of moulds requisite for a work of any given size, may be easily ascertained. For instance, in such an one as has been imagined, in which 24,000 litres (6000 gallons) of juice are produced daily, yielding 2370 litres (610 gallons) of syrup, it would be requisite to have 48 moulds for each day; or, as each mould requires 30 days to clear itself, it will be necessary to have 48 X 30=1440 moulds, and as many pots or receivers, for a manufactory capable of working off 4000 tons in 4 months. Each mould thus serves four times in the season; but perhaps the safer way will be, to have about 1800, to provide against contingencies. In many beet-root sugar manufactories they make use of large oaken moulds, well hooped, containing 200 litres (45 gallons); but care must be taken to keep the hoops tight, lest the syrup should escape at the joints. However, it is next to impossible entirely to prevent this, and therefore this kind of mould is not to be recommended. § 2. Operation of Filling the Moulds. When a pan containing 1185 litres (305 gallons) of syrup has been poured into the moulds, it will be necessary to prepare a number of moulds corresponding to this quantity ;-which will be 24, each containing 12 gallons. Eight or ten hours before filling, these 24 moulds should be laid in water, for which purpose a large wooden cistern (bac à formes) is provided in a convenient situation. These moulds have all a hole at the bottom, through which the molasses drains; but as they are to be filled with sugar in a liquid state, this hole is temporarily stopped up, either with clay or a cork. When they are all corked, the workman proceeds to the planting (plantage) of them, which means the setting them on end ready to fill, and this usually occupies two rows. A workman then, by means of the iron spatula, detaches the the grain which adheres to the bottom of the cooling pan, and continues stirring the contents till the pan is emptied. A second workman then takes a sort of basin suited to the purpose, called a filling out basin, (bassin d'empli) which is filled by a third man, by means of the ladle, with syrup from the pan to within a few quarts of its capacity. It is then poured from the basin into the moulds, taking care not to give it all to one, but to divide the charge between two or three moulds. After this, a similar quantity is poured into other two or three moulds, and so on till the whole 24 have received nearly an equal quantity. This is called a round. When one round is finished, another is begun in the same manner, till the moulds are full; and this ought to complete the discharge of the cooler. To expedite the work, two men should be employed at the basins; whilst one is filling the moulds, the other may be charging the basin at the pan. Whilst filling, a moderate temperature ought to be kept up; say 15 to 20° R. (67 to 77 F). In a general way, the syrup, in a few hours after the moulds are filled, is covered by a crystalline crust, if of good quality, but with a mere skin if not so rich. In every case, the sugar ought to begin to crystallize at the bottom and sides of the mould, layer on layer; so that in 24 hours after filling, all the crystallizable matter, which ought to form in this first operation, is nearly precipitated. During this time, the sugar cools, a contraction takes place in the mass, and if the moulds have been filled at a suitable temperature, this contraction manifests itself at the surface by a slight depression towards the middle. This bespeaks a good boiling (bonne cuite), and a good filling (bon empli). CHAP. XII. On conveying the Moulds to the Refineries, (Purgeries), and Purifying the Brown Sugar. The moulds, after cooling, contain crystallizable matter saturated with a mother liquor or syrup, which must be got rid of. To this end, 36 or 40 hours after the filling out, and when the temperature has fallen to about 20° R. (77 F.) they are taken into the refinery No. 1, where they undergo the first purgation. There the corks or other stoppers are taken out of the bottoms of the moulds, and each mould is placed on its receiver in a vertical position. The moulds, as soon as they are unstopped, give out molasses, which runs into the receivers below, and as this at first is a tolerably rapid operation, the pots should be carefully watched, in order to change them when full. They are emptied into a cistern capable of holding a large quantity. These moulds ought to remain a fortnight in the refinery No. 1, where the temperature should only be 12 to 15° R. (60 to 66° F). There they give out full two-thirds of their molasses. Both the refineries (No. 1. and No. 2.) ought to be situated at a convenient distance from the filling place, and, if possible, adjoining each other. No. 1, which is only at a temperature of 12 to 15° R., has not the power to separate the sugar from all the molasses which it contains, because, to do this a higher temperature is necessary to liquefy the molasses, and make it flow more readily. For this purpose, the moulds, after 15 days' running, in No. 1, are removed into the refinery No. 2., where a temperature of 40 or 50° R. (122 to 145 F.) is kept up. There, they are placed evenly on the pots; but before this, to facilitate the flow of the molasses, it is advisable to run an iron bit into the opening at the bottom of the mould, in order to make a circular hole in the cone of sugar. The moulds remain for a fortnight in the refinery No. 2, after which time, they will be well purged, and the brown sugar may then be separated. not If, whilst changing the pots, it is observed that a mould does run, and that from its weight, &c., there is reason to suspect |