56 BO TANICAL GAZETTE 
rately se with the body, so that by means of the leveling scre 
it can be made horizontal. ; 
The optical parts consist of a ain eyepiece, 1" and 3" objecti 
Fixed in the focus of the eye lens of the ocular is a microm 
_ divided into tenths of a millimeter. ; 
The method of using the instrument is so obvious that it needs : 
special explanation.— CHARLES R. ee University of Wiscons. 
Madis son. 
