642 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Geneva Co.'s Comparator.— The Geneva Society for the Construction of 

 Physical Instruments constructed for the Bureau International des Poids et 

 Mesures, at Paris, the comparator shown in fig. 160, for determining the 

 co-efficients of dilatation of divided metre scales. In this four Microscopes 

 are made use of.* 



Fig. 160. 



* Cf. description in the ' Memoires du Bureau International des Poids et Mesures.' 

 The two Microscopes on the stone pillars were made by MM. Brunner Freres, of Paris. 



