244 



Table A. — Various Engines in which the Boiler is at 140°, and 

 the Condenser at 30°. 



5. Note regarding an Experiment suggested by Professor 

 Robison. By Professor J. D. Forbes. 



In his memoir of Dr Chalmers, lately read to this Society, Mr 

 Ramsay has referred to an experiment which Dr Chalmers was 

 anxious to have performed on the tide-wave in the Bay of Fundy. 

 The object was to determine the earth's density by the attraction of 

 the tide-wave on a plummet or spirit-level, on the same principle as 



