95 
and gives with alkalies compounds soluble in water which 
are true soaps. It is, however, probably not a natural con- 
stituent of cotton fibre, but rather an impurity derived from 
the oil of the seed which escapes and diffuses itself among 
the cotton before or during the process of ginning. It 
might also have had its source in the oil and fat, used for 
greasing the cotton spinning machinery, since the author 
employed yarn in all his experiments. Persons practically 
conversant with cotton spinning affirm, however, that if 
ordinary care be taken, it is impossible that the cotton can 
become contaminated with anything of a fatty nature; 
during its conversion into yarn. 
The colouring matters obtained in these experiments are 
without doubt the substances to which raw cotton owes its 
yellowish or brownish colour. The author was able to 
distinguish two bodies of a dark brown colour, which occurred 
in all kinds of cotton examined by him. Of these one is 
easily soluble in cold alcohol, and is left, on evaporation of 
the solution, as a dark brown, shining, brittle, amorphous 
resin, which is transparent in thin layers. In boiling water 
it softens and melts to a pasty mass, which becomes hard and 
brittle again on cooling. When heated on platinum foil it 
burns with a bright flame, leaving a very voluminous coal. 
It is nearly insoluble in ether. It dissolves easily in concen- 
trated sulphuric acid and glacial acetic acid, with a brown 
colour. It also dissolves with ease in caustic and carbonated 
alkalies, giving dark yellowish -brown solutions, from which 
it is re-precipitated by acids in light brown flocks. The 
other colouring matter resembles this in most of its properties. 
It is, however, much less soluble in alcohol. Cold alcohol, 
indeed, dissolves only a trace, but in boiling alcohol it 
dissolves with tolerable facility, being re-deposited, on the 
solution cooling, in the form of a brown powder. This 
powder, when filtered off and dried, forms coherent masses 
