374 



Portable Instrument for acquiring 



plane on which it is described, rises a pillar, the top of which 

 appears at H above the cone I, which can be made to revolve 

 upon it as an axis. — On the surface of the cone is delineated 

 the principal stars visible in England, and the lower edge is 

 divided into 365 parts, representing the days of the year. 



On the top of the pillar is fitted a segment of a circle, K, of 



