27 



plant, but have a marked effect upon the nicotin, increasing it to an 

 extent that is injurious. In France the planters are advised by the 

 tobacco service not to use nitrate of soda, as it seems to produce 

 tobacco without quality and causes fizzing. Cotton-seed meal has also 

 proved in Porto Rico to be a very good source of nitrogen for tobacco 

 raising, and its cost is rather moderate. Cotton-seed meal not only 

 contains nitrogen, but also a small amount of phosphoric acid and 

 potash. On heavy soils or those deficient in organic matter a small 

 application of lime often gives excellent results. 



EXPERIMENTS IN CURING TOBACCO. 



The curing experiments were conducted in three curing sheds: 



First. A frame building, formerly constructed for a storehouse and 

 part of which was used in that capacity during the curing experi- 

 ment. As the large doors were frequently opened in order to enter 

 the building, it materially interfered with the attempt to control the 

 condition for the curing of tobacco. The building was modified by 

 arranging small hinged doors on opposite sides just above the floor 

 and just below the roof. 



Second. A shed was constructed of poles and canvas and covered 

 by a straw roof. The canvas was treated with linseed oil in order to 

 keep out the humidity and painted black so as to darken the interior. 

 The black surface, however, absorbed the sun's heat and readily trans- 

 mitted it to the air within, thus causing the temperature to become 

 too high. This effect was early noticed and rectified by putting a 

 white canvas over the black one, thus reflecting the sun's rays and 

 keeping the interior of the shed cooler. 



Third. A large shed was constructed of board sides and a thatched 

 roof supported by a pole framework. Large hinged doors were made 

 in the sides for ventilation. 



The daily temperature and relative humidity was ascertained in 

 each shed from March 19 to April 23, with the results given in the 

 following table : 



Temperature and relative humidity in three curing sheds, taken daily at 3 p. m. 





Large shed. 



Cloth-covered shed. 



Frame shed. 



Date. 



Tempera- 



Relative 



Tempera- 



Relative 



Tempera- 



Relative 





ture. 



humidity. 



ture. 



humidity. 



ture. 



humidity. 



1904. 



0 



Per cent. 



° F. 



Per cent. 



o F 



Per cent. 



March 19 



76.5 



74.0 



80.0 



61.0 



82.0 



65.0 



March 21 



76.0 



76.0 



79.0 



60.0 



81.0 



63.0 



March 22 



70.0 



90.0 



71.5 



83.5 



74.5 



78 0 



March 23 



74.0 



82.0 



76.0 



72.0 



78.0 



79.0 



March 24 



76.0 



82.0 



76.0 



77.0 



77.0 



83.0 





74.0 



80.0 



74.5 



78.0 



77.0 



77.0 



March 26 



78.0 



71.0 



78.0 



65.5 



79.0 



69.0 



March 28 



74.0 



86.0 



74.0 



82.0 



74.0 



84.0 



March 29 ... 



78.0 



75.0 



78.0 



69.0 



79.0 



71.0 



March 30 . 



74.0 



86.0 



73.5 



88.5 



74.0 



78.0 



April 4 



79.5 



64.0 



80.5 



61.0 



85.0 



62.5 



April 5. 



82.0 



51.0 



83.5 



82.0 



84.5 



57.5 



April 6. 



72.0 



91.0 



71.0 



90.0 



74.0 



82.0 



