DETERMINATION 



OF THE 



FORCE OF GRAVITY 



AT 



OGASAWARAJIMA. 



An excursion to Ogasawarajima (Boniu) for determining the force of 

 gravity was undertaken by the physical students of Tokio University during 

 the summer vacation of 1884. The opportunity was taken advantage of for 

 making determinations of some of the magnetic constants for the island. 



The object of the excursion was to train, during the summer vacation, 

 these physical students in making precise measurements. It was hoped, at the 

 same time, that the result might be of value as a contribution to science, since 

 the force of gravity near Japan shows a slight excess over the values obtained 

 from ordinary formulae, and remarkably so at Ogasawarajima (Benin) according 

 to Capt. Leutke's observations and consequejit reduction by Baily.* 



The other memVjers of the party were Messrs. Sawai, Hayasaki and 

 Saneyoshi, students in the physical section of the university. The pendulum 

 experiments for the determination of the force of gravity wore conducted by 

 Mr. Sawai, both at Tokio and Ogasawarajima, except a few which were 

 performed by myself as a check upon his operations ; magnetic constants 

 were determined by Messrs. Hayasaki and Saneyoshi ; and the chronometer 

 rating was conducted by me both at Tokio and Ogasawarajima. 



• Encyclop«D<lU Britnnica. Eiglilli EJ. Vol. IX, Art. " Figure of the Eartb." 



