OBSERVATIONS UPON COTTON. 397 



of staple, and it is a satisfactory one; but it is very evi- 

 dent that it has no pretensions to be exact, and can only 

 give a rough average of the length of the hairs. The latest 

 reports of experiments upon cotton that I have seen are 

 by Captain J. Mitchell, of the Grovernment Central Mu- 

 seum in Madras, dated the 2ist and 25th April and loth 

 June 1862; they are addressed to the Madras Govern- 

 ment, and published and circulated by the order of that Go- 

 vernment. In this report. Captain Mitchell gives a large 

 number of micrometer-measurements of the breadth of the 

 hairs in eighteen samples of cotton ; I think these mea- 

 surements leave nothing to desire, and I have pleasure in 

 drawing the attention of the Society to them. But Cap- 

 tain Mitchell desired to extend his researches to the de- 

 terming the length of the hairs ; and, speaking upon this 

 point, he writes, " It is with much regret that I am 

 obliged to say that I have not been able to devise any easy 

 and practical method of measuring single fibres. The ex- 

 ceeding tenuity of the fibre (say, as a mean, _^?^^th of an 

 inch in diameter) renders it impossible to apply it to an 

 ordinary scale; and the only method I can see is to 

 cement them to a glass slide, which can then be applied 

 to a scale ruled on glass for that purpose. This is exceed- 

 ingly tedious, and very trying to both eyes and head, from 

 the impossibility of seeing the fibres without a lens ; I 

 therefore abandoned it for the method adopted (I believe) 

 by the broker and manufacturer, of repeatedly drawing a 

 small portion through the fingers until it appears to be 

 nearly all in a line, and then measuring the small tufts.^' 

 And in another part of the report the writer gives figures 

 and diagrams of the measurements so taken. Difficulties 

 disappear by labour and application. I am now able to 

 measure individual fibres by a simple and exact method, 

 and with tolerable rapidity. The necessary appliances 

 consist of a piece of window glass, in the centre of M^hich 



