146 Journal of the Department of Agriculture. — Aug., 1922. 



Sonietiiiies the tobacco lumping immediately above these wet ba<i^s 

 cures out more of a red than of a yellow colour. The reason is that 

 when the wet sack is placed on the hot flues, too much steam i» 

 evaporated which on condensing cause drops to form on the leaf 

 immediatelj- above them. For this reason it is far more satisfactory 

 to place straw or grass on the floor of the barn, and to wet it just 

 sufficiently to have the right amount of moisture in the barn. If the 

 dift'erence between the wet and dry bulbs of the hygrometer could be 

 maintained at 3.5 degrees, the yellow colour would develop much 

 more rapidly. As the temperature is increased, moisture will have 

 to be added more frequently. 



Although the yellowing of the leaf will continue until the tem- 

 perature is raised to 120° F., it is preferable to have a distinctly 

 yellow colour before the thermometer registers more than 100° F. 

 The value of the crop is often reduced by those growers who fail to 

 get rid of the green colour before fixing the colour. As soon as the 

 original green colour has disappeared the temperature is raised to 

 about 110° F., and when the proper yellow colour has developed the 

 temperature is increased to 115° or 120° F. From 100° F. the 

 moisture must be gradually reduced in the barn. For every 5 degrees 

 the temperature is raised above 100 degrees the difference registered 

 between the dry and wet bulbs of the hygrometer may be allowed to 

 increase about 2 degrees, so that when the temperature stands at 

 115° F. there will be a depression of about 10 degrees, or if it is taken 

 up to 120° F. the difference will be about 12 degrees. 



Fixing the Colour. — This is the second stage of curing, commonly 

 referred to as the critical period. It commences as soon as tlie leaf 

 is properly yellow. The first aim of the grower now must be to 

 remove the moisture as fast as it is given off by the leaf, and under 

 no circumstances must moisture be allowed to collect on the leaf. The 

 ventilators are consequently opened just enough to remove this mois- 

 ture. If the moisture is alloAved to collect on the surface of the leaves, 

 there will soon be a change in the colour to red or brown. On the 

 other hand, if the tobacco is killed too quickly by raising the tem- 

 perature befoie most of the moisture in the leaf has been removed, 

 the tobacco wall scald, that is, it will turn a greenish black colour. 



In order to get the best results the barn must be ventilated as 

 described above, and the temperature must be gradually raised until 

 the thermometer registers 130° F. When the ventilators are first 

 opened it is advisable to keep the temperature at 115° or 120° F. for 

 a while. The fire must be increased as the ventilation is increased, 

 so as to keep the temperature in the barn constant. As soon as the 

 tips dry, that is, when they begin to cure, the temperature is in- 

 creased to 125° F., and held until the lower portion of the leaf is 

 dry, when it is increased to 130° F. until the web of the leaf appears 

 to be dry. The colour will now be fixed. 



Drying the Leaf. — The leaf must then be dried thoroughly. The 

 temperature is raised to 135° F., and held for a few hours, when it is 

 again increased to 140° F., and kept until the leaf is thoroughly 

 dried out. As most of the moisture is removed from the tobacco the 

 ventilators should be nearly closed, and the temperature increased to 

 about 165° F., which should be raised at the rate of 5 degrees an 

 hour. This temperature is maintained until the midribs are properly 

 dried out. 



