118 



Mr. Fryer stated that, with a view of ascertaining whether 

 the barometer was subject to minute oscillations inappreciable 

 by the ordinary method of observing, he had placed an aneroid 

 barometer under the microscope, using the quarter-inch object 

 glass, and, by bringing one of the stricc on the surface of the 

 steel index into focus, he was able, by means of the micro- 

 meter, to observe a movement of the 20,000th of an inch. 

 The index a})peared to be in constant motion, but at present 

 he was not prepared to lay any set of observations before the 

 Society. Mr. Fryer also suggested, for the same purpose, 

 the use of a barometer filled with the oleine of olive oil, such 

 an instrument being free from the disturbances caused by the 

 watery vapour present in the water barometer and exhibiting 

 a greater range. 



PHYSICAL AND MATHEMATICAL SECTION. 



April 25th, 18G1. 



Mr. MosLEY read an extract from a letter received by him 

 from Dr. Martin, of Lisbon, in which were enclosed a series of 

 meteorological observations taken at that place, from the 6tli 

 to the 12th February last, both inclusive. 



Mr. Vernon produced a printed series of meteorological 

 observations made at Sydney and Paramatta, in 1857, 1858, 

 and 1859, which he presented to the Section. 



Mr. Baxendell gave details of observations which he had 

 made during the last l<ow days on a large and remarkable solar 



