Proceedings of the Royal Society of Victoria. 



In oi'der to make the vibration numbers just given comparable 

 with the Greenwich and Kew results, thoy must be reduced to 

 vacuum and sea-level. For the reduction to vacuum, using the 

 same formula as before, we have : 

 26 



Correction = 0-34. 



:8-269 



1+0-0023x30 



and treating the correction for height of station, in the same way, 

 as General Walker did for Kew and Greenwich (see Phil. Travis., 



V. 1890, A., page 557), viz, 

 A may be put as 86*5 feet, we have 

 Correction to sea-level 



Coii'ection = — -^ in which the height 

 243 * 



86-5 

 243^ 

 Total correction = -I-8-62 



0-355 



The following table shows the concluded vibration number foi 

 each pendulum at the Melbourne Observatory. 



Table II. 



No. of 

 Pendulum. 



Number of Vibrations in a Mean Solar Day, reduced to the Mean 

 Temperature 62° Fahr., infinitely small Arc, and 



To Pressure of Air 

 inches at 32" Fahr 



To a Vaeuum. 



86099-27 

 85999-43 

 86051-06 



86107-54 

 86007-70 

 86059-33 



To a Vacuum and 

 Sea-level. 



86107-89 

 86008-05 

 86059-68 



Comparison of the Vibration Numbers op the Three 

 Invariable Pendulums at Greenv/ich, Kew, Sydney 

 and Melbourne. 



As no swings under low pressure have been observed at Mel- 

 bourne, only the results of swings under high pressure observed 

 at Greenwich and Kew are taken into account in this comparison. 



The following numbers are taken from General Walker's paper 

 in the P/u7. Trans., vol. 1890 A., page 551, 553 and 558, 



