1895.] 



MICROSCOPICAL JOURNAL. 



391 



connected by straight lines would form an isosceles triangle, the 

 pillars of the stand occup3nng the angle opposite the base of the 

 triangle. A vertical line drawn through the gravity center of 

 the stand would be in close proximity to one of the long sides 



PV 



^ 



e 



of the triangle, that is to the border of the area of support, and 

 a small outward force would cause that line to fall beyond this 

 border and consequently upset the instrument. It is here that 

 the horseshoe form may bring relief. It will bring the borders 



