82 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
adjustment is attained by sliding the tube, and the fine by a micrometer 
screw. The qualities of a perfect fine adjustment are delicacy, rigidity, 
and permanency. Mr. Bausch considers that the European is generally 
admitted to be the best, but that its use in any simple instrument is 
precluded on account of its considerable cost. He considers, however, 
that his form of fine adjustment proves an excellent substitute. The 
instrument to which he has applied it has a small japanned iron base, 
the pillar and arm is a single brass rod 7/8 of an in. in diameter, in 
