E. II Kraus — A New Jolly Balance. 563 



L, the reading at N, we have the simplified formula : Specific 



W 

 gravity = -j-. 



The figure shows the balance* with the specimen immersed 

 in water and indicates clearly that the chief advantages of 

 this new form, over other balances in common use, are to he 

 found in the recording of the elongations so that they may be 

 verified if necessary at the end of the operations, and further 

 but two readings and a simple division are sufficient to deter- 

 mine the specific gravity. 



I am under especial obligations to Mr. Ralph Miller, whose 

 skill and experience as an instrument-maker were largely drawn 

 upon in perfecting the balance. 



Mineralogical Laboratory, University of Michigan, 

 February 15, 1911. 



* Made by Eberbach & Son Company, manufacturers and importers of 

 scientific apparatus, Ann Arbor, Michigan. 



