76 LECTURES TO SCIENCE TEACHERS. 



of the depth. The whole balance is inclosed in a case of plate 



There is also the large vacuum balance, constructed by Mr. 

 Oertling from a design of Professor Miller, with contrivances 

 for changing the pans and weights, and putting in or taking 

 out small balance-weights from either of the pans ; together 

 with a large collection of other scientific instruments, all of 

 which will be readily exhibited to you at any time that may 

 be appointed. 



