o 



E E r E T 



ON 



A deter:\[ixatiox 



OF 



THE FOKCE OF GRAVITY 



AT 



SAPPORO. 



An expedition to Sapporo fur the purpose of determining the force of 

 gravity there was undertaken liy ns with tlie permission of the University 

 authorities during the month of August 18S1. We here exjiress onr lieartiest 

 thanks to W. S. Chaplin Esq., Professor of Civil Engineering in the University, 

 wlio accompanied us for the purpose of taking charge of the rating of tlie clirono- 

 meter, and to whom we are indehted for much invalnahlo advice. Our thanks 

 are also due to H. M. Paul Esq., Professor of Astronomy, who kindly furnished 

 us with the chronometer rate during onr Tokio experiments. 



As regards the instrumental appliances and the method of experiment we 

 have followed the example set by Professor T. C. Jlendcnhall in his determina- 

 tion of gravity at the summit of Fujinoyama. The method consisted e.-^seiitially 

 in determining the time of vihration of a so-called invariable i)enduhun at the 

 two localities, at which the intensities of gravity were to be coni])ared. Two brass 

 pendulums were made by the Seirensha for the University and were marked A 

 and D respectively. The penchdum A after being vibrated at Tokio was taken 

 to America by Prof. Mendenhall to be vibrated there, so as to bring Tokio into 

 direct gravity connection with the initial stations in Eurojn- and America, while 

 the pendulum 1' together with an old Katers pendnbnn wen- selected for o\n'^ 

 purpose. 



The pendulum P> consisted of a IkjUow brass cylinder wliose outer diameter 

 was 2.5 c. ni., with a knife-edge at a distance of 11.0 c. in. from one end and a 

 heavy disc of the same metal weighing 2398 grammes attached at tlKMithcr. Its 

 total length was 121. .0 cm. The Kater's reversible ]K'ndulum (by Negretti and 

 Zambra) was made use of after removing one of the knife-edges and idl the 

 unnecessary movable parts. The movable bob, consisting of a lieavy brass 

 cylinder was secured at the lower end in such a way as to keep it rigidly in one 



