The dried leaves of a foreign poisonous plant, most extensively cultivated in many parts of the world, to furnish a species of aliment to the depraved tastes of a large portion of the human race.
Tobacco is a potent narcotic, and also a strong stimulus, and in small doses proves violently emetic and purgative. The oil is remarkable for its extreme malignancy, and when applied to a wound, is said, by Redi, to be as fatal as the poison of a viper. The decoction, smoke, and powder are used in agriculture to destroy insects.
Tobacco being cultivated for the leaves, it is an object to render these as large and also as numerous as possible, and therefore the most fertile soil is preferred. It is very sensible to frost. The plants are raised on beds, early in spring, and when they have acquired four leaves, they are planted in the fields, in well prepared earth, about three feet distant every way. Every morning and evening the plants require to be looked over, in order to destroy a worm which sometimes invades the bud. When four or five inches high, they are moulded up. As soon as they have eight or nine leaves, and are ready to put forth a stalk, the top is nipped off, in order to make the leaves larger and thicker. After this the buds, which sprout from the axils of the leaves, are all plucked; and not a day is suffered to pass without examining the leaves, to destroy a large caterpillar, which is sometimes very destructive to them. When they are fit for cutting, which is known by the brittleness of the leaves, they are cut with a knife, close to the ground; and, after laying some time, are carried to the drying shed, where the plants are hung up by pairs, upon lines, having a space between, that they may not touch one another.
In this state they remain to sweat and dry; when perfectly dry, the leaves are stripped from the stalks, and made into small bundles, tied with one of the leaves. These bundles are laid in heaps, and covered with blankets. Care is taken not to overheat them, for which reason the heaps are laid open to the air from time to time, and spread abroad. This operation is repeated till no more heat is perceived in the heaps, and the tobacco is then stowed in casks for exportation.
In the manufacture of tobacco, the leaves are first cleansed of any earth, dirt, or decayed parts; next, they are slightly moistened with salt and water, or water in which salt and other ingredients have been dissolved according to the taste of the fabricator. This liquor is called tobacco sauce.
The next operation is to remove the mid-rib of the leaves, which is reserved to be dried and ground for snuff. The leaves are then manufactured into a variety of articles, by rolling, twisting, and cutting; but the chief are the making of segars, and the cutting the leaves by a machine into fine shreds, for smoking with pipes, or chewing. The machine by which the latter operation is conducted is a very effective instrument, a knife being made to alternate vertically between grooves, with very great rapidity, while the tobacco leaves, confined in a channel, are gradually moved forward by a regulated quantity of motion under the operation of the knife, by which the shreds are uniformly cut of any required thickness.
A patent for an improvement in the machines used for this purpose, was taken taken out by Mr. Samuel Wellman Wright, in 1828. Instead of the alternating action of a single knife, Mr. Wright has introduced a series of knives, placed as radii to a wheel, which, as they revolve, cut the tobacco into shreds; much resembling in its action the chaff-cutting machine in general use, except that the knives in the latter have a curvature given to them, in order that they may cut with a slicing action, and not with a chop, as in the machine we are about to describe, which may, however, be easily altered according to our suggestion.
Fig. 1, (above) and tig. 2 annexed, represent two elevations or views of the machine, one being at right angles to the other. a is the main axis, set in motion by the drum b; c c is a fly-wheel having hinges d d, to which the cutters e e are attached by screws, (these are best seen in Fig. 1;) other screws f f are employed to adjust and set the hinges d d, so that the cutters shall press close to the front of the box g, in which the tobacco is placed; h h are two screws for pressing the tobacco down; and k a screw, by the turning of which it is pushed forward towards the cutters. This screw is supported in plummer blocks ll, and works in a nut fixed in a massive block m, from which two strong bars proceed to another block in the box g, which presses the tobacco forward by the revolution of the screw. On the axis of the screw is a treble pulley, driven by a cat-gut band from another pulley o, on the axis of a, which admit; of the velocity of the screw being varied according as the tobacco is required to be cut fine or coarse.
When the box requires a fresh supply of tobacco, the fork is turned back from the clutch, and a weight 8, which has been wound upon the axis of a winch t descends, and turning the screw in the reverse direction, brings back the block to the other end of the box g.