1910] BRIEFER ARTICLES 149 
of contact with the ball are at right angles to each other, so that definite 
orientation of the object in either of two planes is possible. A third lever 
draws the plate which fits around the ‘‘shoulder” of the ball down when 
correct orientation has been attained, and makes the whole absolutely 
rigid. 
The knife carrier 2 een horizontally on the column of the knife 
block, and is rapidly adjustable to a height of 1.25 inches by means of the 
screw at the top, the two levers behind clamping it instantly in place. 
Arrangement has also been made for the adjustment of the vertical angle 
of the knife. 
The rigidity and rapidity of the adjustment of this instrument are found 
invaluable in cutting many and long series of wood sections. Its use- 
fulness was demonstrated in the sectioning for Mr. W. P. THompson’s 
work on the rays of the conifers recorded in this issue of the BOTANICAL 
Gazette, and the structure of the instrument is outlined here in the hope 
that others may find it useful. 
No small amount of the credit for the performance of the instrument is 
due to the excellent workmanship of Mr. H. W. SPENcE, who also assisted 
in the designing.—R. B. THomson, U; niversity of Toronto. 
