104 TIUCHOLOUIA MAMMAUl'M : 



It consists of a cylindrical metal box, (ours is of brass,) of a convenient size to hold in 

 the hand, (ours is If 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 1 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 1^ 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 millhead are so graduated, that one revolution of the latter advances the screw just 

 T ^ 7 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 the 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 T ^ 7 of an inch, by Robinson at {^ to ^ 7 of an inch, by Withof 

 at, black, - s }-^, brown, %$-%, and blonde, at y i T of an inch. 



So the same pile lias 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 



OF TAPERING 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 5 ^, l east 



