PROCEEDIXGS OF THE POLYTECHNIC ASSOCIATION. 611 



here improve under culture, in India they decline with improved 

 culture. The reports also confirm the statement that the per- 

 ennial cottons are unfit for the market, and the culture of the 

 cotton tree has been abandoned. 



Dr. Stevens said that the characteristics of cotton may be best 

 understood by considering its object, which is to preserve and 

 distribute the cotton seed. The cell of the fiber is originally 

 hollow ; but collapses, which gives it a twisted and flattened 

 form, thus introducing more air into the mass. One function of 

 the flax fiber is to transmit silica to the plant. The silica is 

 transmitted in the form of silicate of potash ; and when the silica 

 is used the potash is deposited between the cells of the fiber, or 

 even within the cavities of the cells. The cotton fiber has no 

 occasion for the introduction of silica or potash into it ; and this 

 is a radical distinction between the two. The cotton fibers radi- 

 ate from the seed like those of the dandelion ; and the conse- 

 quence is that those on the same seed are all of equal length, 

 giving it a uniformity of staple. Indeed all the cotton in the 

 pod that ripens at the same time will be of equal length. From 

 the peculiarity of the soil and climate of the United States, the 

 seeds ripen almost simultaneously over a large extent of country ; 

 and all the cotton ripening upon the same day will be of equal 

 length. During its growth, cotton requires an alternation of 

 showers with hot weather ; but when the pod begins to break, it 

 requires a period of dry weather. Owing to the Appalachian 

 system of mountains, these wants are supplied. The African con- 

 tinent, in its geographical and geological features, is more sim- 

 ilar to the North American continent than any other upon the 

 globe. In the interior of Africa, the cotton can be planted as 

 successfully as in some portions of the United States ; and pro- 

 bably there will yet be a cultivation of cotton in Africa second 

 only to that of the United States. The uneducated labor of 

 Africa is capable of raising about one bale of cotton to the indi- 

 vidual. In the Southern States, the half-intelligent African is 

 able to raise about three bales to the individual. But the intel- 

 ligent German, upon the same soil and under the same circum- 

 stances, is able to raise about six bales to the individual ; show- 

 ing that it is intelligence after all which produces most cotton 

 upon a given soil. 



The President remarked that he should suppose from the ap- 



