Compkte Factory.—Figs. 1383, 1384 represent a modern sugar-house of economical and convenient design. The cane-mill and engine for driving it, with its cane-carrier and begass carrier G F, are shown on the right. The steam-boilers are iu the house A. The defecators are shown at EL and the clarifier at After the juice is defecated, it passes through the triple effect T, where it becomes syrup, and is clarified in I, whence it goes as required to the vacuum paaa S, where it is concentrated and becomes massc-cuito, of larger or smaller grain as desired. From S, it falls into waggons W, and from these waggons it is discharged into the mixer of the centrifugals at L. These eentrifugals are driven by the engine B, which works the vacuum-pump for the triple-effect and vacuum-pan. The sugar is finally packed in the area P, and delivered at the door on the extreme left of the house.
Maple-sugar.—The rock or sugar-maple (Acer saccharinum)is a tall ornamental tree, flourishing throughout most of the N. American continent. In sections of the United States where it has not been exterminated, the manufacture of sugar and syrup from it is a remunerative adjunct to other farming industries, occupying a period in which little other farm work can be pursued. The apparatus for collecting the sap and manufacturing the sugar, involves a very small investment ; tbe fuel consumed usually consists of the pruniogs of the maple grove, which is benefited thereby ; and at least 90 per cent. of the gross return is net profit.
An interesting point connected with the production of maple-sugar, is the variability of the flow of the sap, dependent on diurnal changes of weather. The rising of sweet sap commences imme diately after the first break-up of the long frost, about mid-February, continuing through March and into April, but varying in different localities and at different seasons. A cold N.-W. wind, with frosty nights and sunny days in alternation, tends to incite the flow, which is more abundant in the day than at night. It is, however, most sensitive to unfavourable changes, and a run of 3 gal. a, day from one tree may almost cease in a few hours, and then gradually recover itself. Hence the yield from day to day is uncertain, and reliable statistics are difficult to record. A continuous course of favourable weather tends to the largest production, a rising and falling supply reducing the total of the season. The flow commences earliest in warm and low situations. A thawing night is said to promote it ; it ceases during S. winds and at the approach of a storm. On the S. and E. sides, it has been noticed to be earlier than on the N. and W. sides of the same tree. There are generally 10-15 good " sap days " in the season, which continues on and off for about 6 weeks ; after this, as the foliage develops, the saccharine naatter is reduced, and the sap is said to be " sour," though a restricted flow still continues. Emerson considers that the sugar-yield depends also on the
character of the previous summer, and that plentiful rain and sunshine prepare for an abundant harvest in the suce,eeding spring. Open winters are thought to render the sap sweetest ; while much freezing and thawing make it most abundant and of the best quality. The sap of isolated trees is richer in sugar than that of those which are massed together in the forest.
The produce of sugar may average 1 lb. to 41-5 gal. of sap, but instances are given of 1 lb. of sugar from 3 gal. of sap. In a good sap season, an average tree will run as much as 3 gal. of sap in a day, occasionally more, and afford about 4 lb. of sugar in the season ; Emerson records cases of 10,20, 33, and 43 lb. of sugar from single trees, but such weights are altogether exceptional. The average quantity of sap per tree would be 12-24 gal. in a season. Trees under 25 years old are seldom tapped, scarcely paying for the trouble, apart from the debility it produces in them. Repeated tapping of mature trees causes no apparent injurious effect : in many instances, trees have been tapped for 40 consecutive years, and it is said that both the quality and quantity of sap are visibly improved after the first tapping.
The trees are usually tapped at a height of 3-4 ft. from the ground, with a fin. auger to a depth of 2-6 in., into which a perforated plug is driven, to lead the sap into the collecting-vessels, or a simple notch 11 in. deep is cut with the axe. One to three taps are inserted in each tree, and have to be removed in succeeding years to fresh places, generally alternated on opposite sides of the tree. In the United States, the large branches are punctured, as well as the trunk. The sap is evaporated either in iron caldrons, or in shallow boilers, 6 ft. long, 21 ft. wide, and about 8 in. deep. Those of copper are preferred to iron, as they are said to yield a whiter sugar. Care is taken to keep the boilers filled up with fresh additions of sap during evaporation, and to stir it well with a wooden spade, till the syrup attains a sufficiently thick consistency (which is ascertained by its " breaking " or crystallizing when dropped into cold water), and exchanges its white colour for golden-yellow. It is strained during evaporation, a small quantity of lime or soda being added to neutralize any free acids that are present, and Lb little white of egg or milk to clear it. After straining and skimming, it is poured into pans or moulds to crystallize, and may be further clarified by gently boiling in tapering cans, with a tap at the bottom, towards which the molasses gravitates, and is drawn off as the crystallized sugar sets. Earthenware pets are said to improve the colour but injure the quality.