178 
POPULAR SCIENCE REVIEW. 
portance to supply artificially to the soil the constituents neces- 
sary for the production of the cotton in its greatest perfection. 
It may be found that the difference between the production of 
the most valuable cotton and that of an inferior description, de- 
pends on the supply of those mineral constituents to the soil 
which are necessary to the proper development of the cotton- 
hair. It has been stated that the ashes of the finest Sea-Island 
cotton contain a larger proportion of the salts of potash, whilst 
inferior kinds contain larger quantities of soda. Such facts are 
of high interest to the cotton cultivator, and seem to point out 
the way of securing the better qualities of cotton. 
But let us now turn our attention to the history of the plants 
which produce this wonderful hair. The genus of plants which 
yield cotton is called by the botanist Gossypnum. This word, 
which is the Latin word for cotton, is said to be a corruption of 
the Egyptian word gotne, which is evidently a form of the 
Arabic k-utun, and has its origin in the same root as our word 
cotton. This botanical genus Gossypium embraces several 
species, four or five of which have been named by botanists as 
affording the cotton of commerce. The family or group of plants 
to which the genus Gossypium is referred, is the Malvaceae 
or Mallow tribe. This family of plants is remarkable for 
its showy flowers, and embraces about thirty-five genera 
in addition to Gossypium. Some of these are well known. 
Besides the common mallow and the round-leafed mallow, 
which are common on all our waysides, the marsh-mallow 
is a British species. In our gardens the hollyhock is 
a familiar example of the size, and beauty, and colour 
of the flowers of this order. If we examine one of the 
flowers of these plants, we shall find that a distinguishing 
feature of them is that the stamens are all united toge- 
ther, forming a column in the middle of the flower, which 
is hollow in the centre, and surrounds the styles, which 
proceed from the germ or ovary hi the middle of the flower. 
These columnar stamens are characteristic of the family ; but 
there is a further mark of brotherhood in this Mallow 
family, and that is, the anthers having but one cell. Usually the 
anthers, which are placed at the top of the filament of the 
stamens, have two cells or compartments, in which the pollen- 
dust is kept ; but in the Mallow tribe each stamen keeps its 
pollen in a single cell. There are many other points of struc- 
ture about these plants which, conjoined with the above, make 
up very strong family features. One of these is worth notice, 
and that is, the arrangement of the petals. If a mallow is 
gathered before its flowers are opened, and the sepals of the 
calyx are removed from the petals, it will be found that the 
petals assume the appearance of having been twisted. It looks 
