392 
Transactions of the Society . 
Pitch. — 36 to the inch. 
Length of Thread on Object- Glass 0*125 in. 
Plain Fitting above Thread of Object-Glass 0*1 in. long, not to 
exceed 0*759 in. in diameter. 
Diameter (C) of Thread on Object-Glass at top of thread not to 
exceed 0*7982 in., or to be less than 0*7952 in. 
Diameter (D) of Thread on Object-Glass at bottom of thread not 
to exceed 0*7626 in., or to be less than 0*7596 in. 
Length of Screw of Nose-Piece to be not less than 0*125 in. 
Diameter of Screw of Nose-Piece (A) at top of thread not to 
exceed 0*7674 in., or be less than 0*7644 in. 
Diameter of Screw of Nose-Piece (B) at bottom of thread not to 
exceed 0 * 803 in., or be less than 0*8 in. 
