104 TRICHOLOGIA MAMMALIUM ; 
It consists of a cylindrical metal box, (ours is of brass,) of a convenient size to hold in 
the hand, (ours is 1} of an inch in diameter, and two inches in length.) The bottom is 
permanent, but the top screws on. In the centre of each end is a circular opening of the 
diameter of ¢ of an inch. A cylinder of this last diameter, extends from the interior sur- 
face of the bottom of the box to that of its top. This cylinder, when the top of the box is 
unscrewed, can be taken out, but when the top is screwed down, remains fixed by a shoulder 
directly opposite to the openings. In the opening at the bottom of the box is a screw 
thread, into which fits a screw 14 inches long; this screw, which is turned by the agency 
of a millhead, and which is seen below the bottom of the box, passes up the small cylinder, 
its end pushing forward every object resting upon it, forcing the other end of the object 
through the superior opening of the box. ‘The thread of the screw and the circumference 
of the milllead are so graduated, that one revolution of the latter advances the screw just 
qty Of an inch. Pieces of cork are cut so as to fit the small cylinder; through the centre 
of one of these pieces of cork is passed a fine needle carrying a thread, by returning it 
again through the same perforation a loop is formed, through this loop pass the hair from 
which the disk is required to be cut, then draw the other end of the thread until the hair 
doubles and passes down through the perforation in the cork. After having applied a 
very small quantity of gum to the perforation around the hair to keep it perpendicular in 
its place, put the cork into the small cylinder, one end of it resting upon thé screw, and 
the other passing through the opening in the top of the box, and remaining exactly level 
therewith. ‘This done, turn the millhead in proportion to the thickness of the disk 
required to be cut, and when the cork makes its appearance above the top of the box the 
distance required, cut off a disk of the cork, with the hair enclosed in it, with a sharp 
razor, ground flat on one side only. These disks may be placed under the microscope in 
the cork, or they may be extracted and viewed separately, as desired. In either method 
the shape of the pile may be seen, and the diameter taken with the utmost accuracy. 
The diameters of pile have been variously estimated by different authors, say, by Haller 
and Mussenchenbroech at ,4, of an inch, by Robinson at 31, to g45 of an inch, by Withof 
at, black, =45, brown, ;4,, and blonde, at -4, of an inch. 
So the same pile has been said to vary in thickness. ‘Thus, according to Weber, the 
thickness of a negro’s wool was, at one point, 0.019 lines in its least diameter, and 0.038 
in its greatest diameter, and, at another point, 0.023 in its least and 0.038 in its greatest 
diameter. Another fibre of negro’s wool is said to have measured, upon four points, as 
follows: 
Greatest diameter. Least diameter. 
0.0425 0.0310 
0.0470 0.0340 
0.0425 0.0295 
0.0410 0.0340 
Or Taperine Hair.—Having found that the hair of Albinos was very tapering, from 
root to point, we took the diameters which were as follows : 
The hair of Mary M. Williams, greatest diameter ;1,5, least ;i5. 
