22 
did *not show cracks and signs of crushing like those from 
the electrical fracture. 
No. 3 was then fired with f inch of powder, and the shot 
penetrated ^ inch into the deal board. 
It was again fired with 1 inch of powder, and the shot 
penetrated 1 inch into the deal. 
Again it was a third time fired with 1 J inches of powder, 
when it burst and the shot only just dented the wood. 
These experiments seem to me to prove conclusively the 
great strength of the tube and the enormous bursting force 
of the electrical discharge. 
“ On the Colour of Nankin Cotton,’' by Edwaed Schunck, 
Ph.D., F.RS. 
Among the numerous varieties of cotton existing in 
commerce there is one which cannot fail to strike the most 
unpractised eye, ’in consequence of the peculiar colour, vary- 
ing from a pale yellow or rather fawn to a brown or reddish- 
brown, which it exhibits. This kind of cotton is generally 
called ‘"Nankin” cotton in consequence of its having been 
used at an early period by the Chinese for the manufacture 
of the fabric called nankin or nankeen, the peculiar colour 
of which is so well known as to need no description. 
Specimens of raw cotton of the colour referred to from other 
countries, such as India, America, the West Coast of Africa, 
and the shores of the Mediterranean are, however, found in 
all extensive collections, so that it cannot be considered as 
a product peculiar to China. In Malta it is, I am informed, 
especially abundant, more so than the ordinary white kind. 
Whether it is produced by a peculiar variety (not to say 
species) of the cotton plant or whether the colour is owing 
to peculiarities of climate, soil, or method of culture in- 
fluencing the plant is, on the other hand, a question not 
easily determined. Considerable doubt indeed prevails as 
to the number of species embraced by the genus Gossypium 
