176 Proceedings of the Royal Society of Victoria. 



Period of one vibration, reduced to 0° centigrade, to infinitely 

 small arc, and to a vacuum, l^eing the mean of three \ seconds 

 pendulums 



At Melbourne (8G-5 feet above sea-level) O'- 5066120 

 At Sydney (140 feet above sea-level) 0'- 5063920 



and taking for the value of ^ at Vienna ^=9-80866 meters as 

 found by Professor Oppolzer by a reversible pendulum in the 

 year 1886, he derived the following values, not reduced to sea- 

 level. 



Melbourne ^=9-80014 meters 



Sydney ^ = 9*79702 meters 



And reduced to sea-level, 



Melbourne ^=9-80020 meters 

 Sydney ^=9-79713 meters 



According to these values, the Indian pendulums should make 

 13-48 vibrations less at Sydney than the number of vibrations 

 they make at Melbourne in a mean solar day. Therefore the 

 difference 8-58 given in Table IV. is too small by nearly 5 

 vibrations, according to Lieutenant Elblein's provisional results. 



This fact casts a doubt either on some of the observations or 

 on the invariability of the pendulums, as the discordance is quite 

 independent of the absolute values chosen as bases, and small 

 differences in the formulae used for computing the various correc- 

 tions could not account for such a large error. It is therefore all 

 the more urgent to swing the Pendulums at Sydney at the very 

 first opportunity. 



The several values of g for Melbourne derived from the above 

 sources are as follows, viz.: — 



By the Greenwich and Melbourne swings, \ o.^ ^ ark- f 

 and the length of the seconds pendulum as \^ "~^~L^^, „ 

 on-io^o. • I ^ ^1, £ 1 I p-= 9-79810 meters 



39-13734 inches at the former place ) * 



By the Kew and Melbourne swings, and \ , , , , ^ .r- n 

 '' ' '■-— 32-14827 feet 



the length of the seconds pendulum as 

 39-14008 at the former place 



\g= 9-79870 meters 



T.,,, • ) i--^ 32-15317 feet 

 Provisional value of Lieutenant Elblein > •=> or^n.^r. 



J = 9-80020 meters 



