PREFACE. 



Concfniing tliy t'dlliiwiiii;- Ijiicl' uu'iiiuir, a lew tliiiii;s oiiL;lit to lir f^iiiil \\"lni;li 

 liL'liiu.j; inciix' ;i|niro|iri:itL'ly in :i [irelauc tliaii clsewliefc. 



1 liiivu already c'Xi)r('s>^i'(l my inilchtcdness fo \ari(iiis jk'vsoiis wlio have 

 cimtriliiiteil fo a greater nr less extent to tlie siieeess iif tlie exi)erimeiital iiives- 

 li'j,Mtiiiii lierein (leseril)eil ; Ijiit I wish tu make speeial ineulioii in this ]ilaee of 

 the iiivaliuihio iissistance remlereil by Messrs. Taiialcadate ami 'J'auaka, fn wlmm 

 was assij^ned the tiislc of making; the pendulum vihratinns hotli in Tokio and 

 on the summit of Fujinoj-ama. These exiierinuaits and the reduction of the 

 ri'snlts involved a far greali'r amount of lalxiur than is at lirst a|i]iarent. The 

 detevniiiialion of tlic actual jieriods <if vibration tVom tlu^ rhrono!;ro]ih sheets 

 was made, in all cases, by ]\Iessrs Tanakachite and Tanaka althongh, in many 

 instances, I liavo rejjeated the measurements, only, however, to verify the results 

 which they had obtained. The faithfulness anil skill with which tViey performed 

 every assigned duty justilied great coiifideiice in their results 



1 am indel»ted to all of tlie members of the party upon tlie summit of the 

 niouuhiin, for aid rouilered in very many ways and I ought particularly to 

 mention .Mr. Yamada who took ii]i"n himself the care and responsibility of 

 transporting the instruments tVum tlie I 'niversity to iIh- siunniil of the nMUntain 

 and back again. 



I must also e.\]iress my thanks to lh(^ Directors ol' the I ni\ci>ity, I\Ir. Kato 

 and Mr. Ilattori, who kindly gi-anted tlii^ use it\^ tliesi.' instnunenis and who 

 aided the undertaking in every way in their |iowei'. 



A considerable portion of the first part of this memoir, on tlii^ Tokio deterin- 

 inatioii, w:ts pubiisheil, in substance, in the .Americaii .rounial of Science, for 

 August bSSÖ, and a portinn of the sei'ond [lai t, on the I'^ijiiioyania deteiininatioii. 

 in the same journal for Fcbiuary 1881. 



Finally, it seems only justice to call allenlion to the fart that the piiiiling 

 of the memoir has been done entirely by native workmen, who are at once un- 

 faniiliai' with the la nu nage in wliirli it is writti'ii and iinur. piaiiiird w illi Ihi' nii'llhuls 



of "making nji' whieh are so widl mulerst 1 in every westein printing oltice. 



This fiwt, together witli thi' ilillicidty and in some cases, impossibility oi obtain- 

 ing perfectly suitaiile type for the reiiresmtatinn (if mil liiinil ii:il lui miihe, will 

 lie siillicieiit excuse fur anv sh"i trnmin^s In tic nieebanii-al exeenliun uf IJie 

 pampldet. 



T. (", M. 

 Tokio-Japan. January 1881. 



