SUGAR from different Plants.—In some parts of North America, particularly in Canada, a kind of sugar is prepared from the juice which issues upon wounding or boring certain species of the maple-tree, one of which is named from hence the sugar-maple; as also from the wild or black birch, the honey-locust, and the hickory. The maple is most commonly made use of for this purpose, as being the richest, and as best enduring the long and severe winters of that climate. The juice is boiled down, without any addition, to a thick consistence; then taken off from the fire, kept stirring till its heat is abated, and set in a cold place; where the sugar quickly concretes into grains, resembling common brown powder-sugar.
The trees are tapped early in the spring, about the time that the snow begins to melt. It is observable, that when the weather begins to grow warm, they bleed no more; and that, after the bleeding has stopped, they begin to run again upon covering the roots with snow. The more severe the winter has been, the juice is found to be richer and in greater quantity. The trees which grow on hills or high land yield a richer juice than those which are produced in low countries; and the middle-aged than the young or the old.
Mr Kalm informs us, in the Swedish Transactions for the year 1751, that one tree, if the summer does not come on hastily, will yield about forty-two gallons of juice (English wine-measure), and that the quan-
tity which issues in one day is from three to six gallons: that eleven gallons of juice of middling quality give a pound of sugar, and that sometimes a pound has been gained from three gallons and a half: that two persons can in one spring prepare commodiously 200 pounds. He observes, that this sugar is weaker than that from the sugar-cane; but that for some purposes it answers better, as for chocolate and preserves. It is likewise esteemed more medicinal. Considerable quantities are brought annually into Europe, particularly France, and there employed in disorders of the breast. It is reckoned that a pound of common sugar goes as far in sweetening as two pounds of maple-sugar.
The large maple, commonly called sycamore-tree, bleeds also in Europe a sweet juice, from which an actual sugar has been prepared. In the Transactions above-mentioned, for the year 1754, there is an account of some experiments made in this view upon the Swedish maple. Eight trees, none of them under thirty years, bled in four days fourteen gallons of juice; which, inspissated, gave two pounds and a half of brown-sugar. Another time, the same eight trees bled in three days ten gallons and a half; which yielded one pound four ounces of sugar, with half a pound of syrup. It is the saccharine juice of the maple-tree, which, exuding upon the leaves, renders them so apt to be preyed upon by insects.
The common birch bleeds also a large quantity of a sweetish juice, which yields, on being inspissated, a sweet saline concrete, not however perfectly of the saccharine kind, but seeming to approach more to the nature of manna.
There are sundry other vegetables, raised in our own country, which afford saccharine concretes; as beet-roots, skirrets, parsneps, potatoes, celeri, red-cabbage stalks, the young shoots of Indian wheat. The sugar is most readily obtained from these, by making a tincture of the subject in rectified spirit of wine; which, when saturated by heat, will deposit the sugar upon standing in the cold.