ASTRONOMICAL INSTRUMENTS. 

 Fig. 131. 



121 



rack- work, may be applied to either of the two stands, as 

 occasion may require, the sockets on the top of both being 

 made exactly of the same size. The sliding rods may be 

 applied to the feet of the brass stand, so that the telescope 

 may be used with the same advantages on one as on the 

 other. 



11 



