222 PROCEEDINGS OF SOCIETIES. 
prepare a memorandum on the subject of measurement, to be for- 
warded hereafter. 
P.S.—1. In a note dated 22nd instant, with which I was 
favoured, His Excellency Sir W. Denison svas good enough to 
suggest the possibility of obtaining a better knowledge of the 
structure of cotton fibres by means of transverse sections. 
2. The subject is a very difficult one, as the sections require to 
be so exceedingly thin, less than one-thousandth of an inch. I 
am not, therefore, surprised that I did not succeed. But my 
failure to obtain transverse sections, properly so called, led me to 
cut as obliquely as possible through the fibres, and this method 
has revealed all I wanted to know, for the sloping extremities of 
the fibres thus obtained show beyond a doubt that in all, except 
the very thinnest, there is a greater or less amount of secondary 
deposit, which in the round, roundish, and flattish ones is carried 
to such an extent as to form (?) homogeneous solid body, instead 
of a hollow cell or tube, but in the flattish fibres the deposit 
appears thickest at the margins. The same result was subse- 
quently arrived at by examining the cut extremities of other 
portions with a half-inch object glass and Lieberkuhus’ reflector. 
This method of examination not only confirmed the results of the 
other, but exhibited also the very irregular form of the transverse 
section. 
3. I have also examined the fibres by polarised lhght, upon 
which I find the thin flat fibres have little or no action, being 
nearly, sometimes altogether, invisible when the axes of the 
Nicol’s prisms are crossed. But they become visible when a film 
of selenite is interposed between them and the polarising prism. 
25th April, 1862. 
Form and Character of the fibre in the several samples. 
Pro- 
gressive 
numbers, 
No. 1/The majority of the fibres flattish with thickened walls, a 
few flat and very thin, still fewer round and solid looking. 
» 2 The flat thin fibres and those with thickened walls in about 
| equal proportions, a few round solid looking. 
,, 3 Fibres chiefly flattish with thickened walls, some round and 
roundish solid looking; but very few of the very thin 
kind. 
Many flat and very thin fibres: others flattish with the 
| walls but moderately thickened, a few round solid look- 
ing ones. 
» 5 The thin flat fibres present in considerable number, fibres 
| generally but little thickened and having a delicate ap- 
pearance. 
” 4 
