102 



SCIENCE PROGRESS 



applied under its centre. It consists of an elaborate apparatus for 

 the support and adjustment of the plate and knife-edges ; a 

 measuring microscope reading in two rectangular directions by 



a new method to the thousandth of a millimetre, for measuring 

 the dimensions of the plate in situ ; a specially constructed form 

 of balance, one end of the beam of which carries an agate 



