MEASITEEMENT 



OF THE 



T 



FOECE OF GEAYITT 



Alf 



NAHA AND KAGOSIIIMA. 



Accordiog to the direction of the university authorities, an expedition to 

 Naha (Okinawa-ken) was undertaken by the physical students, during the 

 summer of 1882, with the principal object of making a comparison of the 

 force of gravit}- there with that at Tukio. The determinations of the force of 

 gravity at different localities in the Pacific Ocean has of late become of pecu- 

 liar interest, us the determinations hitherto made tend to show that the iuten- 

 sities at places near Japan are decidedly greater than those calculated from 

 the usual formulaj. To furnish data which might aid in finally deciding this 

 point formed, therefore, the principal object of the expedition. 



The party consisted of ilessrs. Yam.nguchi, Yamada, Tanakadate and 

 myself. Tlie magnetic observations, which were made along with the pen- 

 dulum experiments, were conducted by j\Ir. Yamaguchi. Mr. Yamada, who 

 acted as treasurer of the part}', undertook, besides other duties, the trans- 

 portation and the general charge of the instruments. Mr. Tanakadate, who 

 had been previously on a similar expedition to Sapporo, took upon himself the 

 tank of chronometer rating and latitude observations, as being the only one 

 of tlie party who bad bad experience in practical astronomy. The transit 

 instrument used for time observations was the property of the Surveying 

 Bureau. We take the opportunity of thanking the Director, Mr. Arai, for 

 Ilia kindness in granting us the use of it. This instrument not being suitable 

 for latitude observations, we employed fur this purpose a sextant belonging 

 to the university. 



The mode of experiment was essentially siinilar to that used by i'rdl'. 

 Mendeuhall iu his Fuzinoyama experiment, aud followed by Mrss. Tanakadate, 



