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the degree of heat required at the various stages of the curing process. The Snow barn principle is preferred by the North Carolina experiment station, because it enables temperature and moisture to be more closely regulated than in old-fashioned barns. Approximately, a pound of water for each plant must be driven out in about 100 hours. According to Mr. Ragland's methods, there are four stages in the operation:
1. The yellowing process, requiring 90° of heat and lasting from 24 to 30 hours.
2. Fixing the color, requiring from 16 to 20 hours at a temperature ranging from 100° F. at the beginning, to 120° at the close.
3. The curing process, requiring for 48 hours a temperature of 120° to 125°.
4. The curing of the stalk and stem, which requires from nine to ten hours with a heat of 125° to 175°, increased at the rate of 5° an hour.
Mr. Kagland himself subsequently modified these regulations, by advising the heat to be put under the tobacco as soon as out, and the temperature put at 90° for three hours and then advanced rapidly to 125°, or as high as the tobacco will bear without scalding, letting the heat remain at this high temperature for only a few minutes, and then allowing the temperature to descend to 90° again. This process he calls "sapping." The sap cells are opened, the water comes to the surface of the leaves, and the yellowing process is hastened, requiring only from four to eight hours, instead of from 24 to 30 hours by the old formula.
Mr. George L. Wimberly, a successful tobacco grower of Edgecombe county, lying in the Champaign district of North Carolina, gives some information which is appended. Mr. Wimberly strips the leaves from the stalk in hat vesting, and the method of curing is varied somewhat from that used in curing tobacco on the stalk. o
He says: "Our barns are simple structures, 20 feet Square, 16 feet from the ground to the plate, with a roof not too sharp, a moderately flat roof being, in the opinion of experienced tobacco farmers, the best. In curing, we generally start at 95°, and consume from 24 to 30 hours between that heat and 110°. From this point, advance two and one-half degrees per hour* until 120° is reached, where that degree of heat is retained for about four hours. Then it is advanced to 125°, where it remains about the same length of time. From that point, the heat is advanced slowly to 135°, where it remains until the leaf is thoroughly cured. When this is done, the critical point is past, and the heat can be moved up five degrees an hour until it reaches 170°, where it should remain until the stem is cured so perfectly that it will break like a dead twig. The fire is then drawn, the door opened, and in 24 hours the tobacco is ready to come out | of the barn and go to the pack house. It takes four days to cure a barn of tobacco, and in a 20-foot barn there will be about 800 pounds."
Mr. R. B. Davis, who raises yellow tobacco very successfully in the Piedmont district of North Carolina,
FIG. 57. • PSYCHKOMETEB.
•The instrument consists of two accurately graduated thermometers, of which the bulbs are placed at Borne distance apart. The bulb of one is surrounded by thin muslin, which is connected by a wick of clean cotton to a cup hung a short distance below, and which, while the Instrumentt is in use, should contain more or less of dlst illed, or clean, rain water. The water from this cup is drawn upward through the wick to the muslin that surrounds one of the bulbs, and thus the surface of this bulb is kept constantly moist, while that of the other bulb is dry. Now, the water on the surface of this wet bulb will evaporate into Ike all about It more or less rapidly, according as the all says that the yellowing process should be done at 90° (80° if the weather is cool), and should last from 18 to 30 hours, until the desired color is obtained. The drying, or curing, is then effected by regulating the temperature so as to have 95° for two hours, 100° for two hours, 105° for two hours, 110° for two hours, 115° for two hours, 120° for six hours, 130° for two hours, 140° for two hours, 150° for two hours and 160° for 24 hours, the last temperature being kept up until the stalks and stems are cured.
A very interesting case was reported by the Border Review. A barn 18 feet square, four firing tiers high, and containing 450 sticks, or 3150 plants, was successfully cured by the following process: The tobacco was of old-field growth, long leaf, but thin and light. The temperature was run up to 90° in six hours, then to 100° in six hours, then 110° in six hours. The leaf was thoroughly yellowed at the expiration of 18 hours. The temperature was then advanced 120° in six hours; to 125° in six more; to 130° in six hours; to 140° in three hours, where it was allowed to remain for six hours. At the end of this time the leaf was cured. Then the temperature was run up to 150° for three hours and held at that point for three hours, then to 170° in 12 hours, where it stood for 12 hours, until the stalk was
already contains more or less of moisture,—the more moisture the air contains, the less rapid will be the evaporation, and vice versa. Since water, in evaporating, absorbs heat, the temperature of the wet bulb is lowered more or less, according as the evaporation is more or less rapid. Hence, by noting the difference in the temperature registered by the two thermometers, we form an idea of the moisture of the air, —the greater the difference registered, the dryer the air, and vice versa. When the two thermometers register alike, the air in contact with the wet bulb is saturated with moisture, so that it can hold no more, and hence evaporation has ceased. In dry, summer weather, the difference registered by the two thermometers may amount to fifteen or more degrees. By using prepared tables, the absolute relative humidity of the air may be determined by the psychrometer, but for our present purpose, the depression of the wet bulb is all that is necessary to use. The tobacco leaves while in process of curing being moist, the evaporation from them will follow the same law as from the wet bulb, hence a psychrometer hung among the plants in the curing house will give an indication at any time of the rate at which the moisture is passing off from the tobacco.
dry. The result was a perfect cure of a lemon color requiring only 75 hours.
Another modification of the process was made by Mr. T. 0. Anderson, of the Champaign district of North Carolina, which he says will always give good results if the tobacco yellows well and is allowed to remain on the hill until it is thoroughly ripe. His instructions are, that it must be cut and put in the barn as soon as possible, from five to seven plants on a stick, arranging the sticks in the barn ten inches apart in warm weather and eight inches in cool weather. Start the fires at once. In warm weather run the temperature up to 100°; in cool weather to 75°. Keep the heat to this point for six hours; raise to 105°, hold at this point for five or six hours; raise to 110°, at which point hold for 10 or 12 hours, until the tobacco is yellow enough to commence drying the leaf; then raise to 118° or 120°. When this temperature is reached, throw the doors open and reduce the heat to 105°; then run the heat up to 120°; open the doors and let the temperature fall back to 105°. Repeat this four or five times. This dries off the sweat that causes trouble at this stage of curing. Close the doors then and hold the heat at 120° for three hours, or until the leaves on the bottom tier are about half cured, then raise the heat to 128°. Open the doors and reduce the heat to 115°; then close the doors and elevate the temperature to 130° in three hours; then to 135° in five hours, or until the leaves are cured; then to 145° for three hours; then to 150° for two hours; then 155° for three hours; then to 160° for two hours, and so on to 180°, and hold at this until stalks and stems are cured.
It is apparent, from a careful study of these different formulas, that every carer must exercise judgment as to when to increase and when to decrease the heat. He must watch some particular plant and be governed by its condition. The greatest danger to be feared ia the reddening, "splotching" or sponging of the leaf during the second stage, when the color is fixed. The sweating of the leaf at this period must be checked, by admission of air to the barn by the opening of all doors and windows, and by opening a space between the logs on the side opposite the door. Mr. Ragland says, just at this point more failures are made than at any other stage of the process. "Five curings are spoiled by forcing too fast, to one from going too slow."
Captain E. M. Pace, of South Carolina, gives the following directions for curing when the leaves are
FIG. 68. STOVES AND FLUE8 FOR CURING SEEDLEAF.
stripped from the stalk. "Take off the thoroughly ripe leaves after a light shower, or early, when the dew is heaviest; string and run the tobacco in the barn before it has time to wilt. In case there is no light shower, use plenty of water around the sides of the barn below the first tiers. Suspend a plank over the main flues, to keep the heat from scalding the tobacco on the lower tiers (these can be removed after the sweating). Use pans filled with water on the flues and furnace. This will assist in producing a moisture, or warm vapor, thereby aiding the leaf to sweat. The entire barn must sweat freely. Heat and water will do it. Stop the use of water on the sides and floor as soon as the leaf begins to sweat. When the leaf begins to sweat, say at 110°,