96 E, F. J. Love, : Gravity Determinations. 



haviour of one clock to that of another, even of the same construc- 

 tion, the fact is significant. Hecker also found that the mere stopping 

 and restarting of his own clock altered its rate, on one occasion, 

 by nearly 1^. sec/day; so it had peculiarities of its own. 



Appendix 3. 



No corrections need be applied to the Sydney figures of 1882^ 

 or to the Kew figures, for the change in pressure factor from 0.32 to 

 0.34; the diminished pressures, under which they were obtained, were 

 purposely chosen so as to render the pressure reductions to 26 'in., 

 at the mean temperatures of the respective observations, nearly or 

 quite evanescent. 



Appendix 4. 



Mr. Curlewis informs me that the Perth observatory is built on 

 solid sand; for reasons given in his letter, the sand appears to be of 

 great depth. I have therefore assumed 2 '2+0 -2 as a sufficient ap- 

 proximation to the density required for computing the Bouguer re- 

 duction. 



