MAGNETIC SURVEY OF JAPAN. 231 



and the smallest of one. These maps have been the basis of all 

 subsequent ones ; and for many places in Japan Inö's measurements 

 of latitude (and longitude) are the only ones which have as yet 

 been made. 



On completion of the survey, Takahashi published an epitome 

 of the results in a book having the title, '" luö's Table of Latitudes 

 and Longitudes." From certain remarks in the preface to this work, 

 it would aj^pear that Inö rather doubted the truth of the magnetic 

 variation, and was inclined to refer its appearance in Europe to care- 

 lessness either in the construction ov handling of the compass needle. 

 There can be little doubt, however, as to the accuracy of Inö's own 

 observation that in Japan at that time the mean direction of magnetic 

 north coincided practically with the direction of geographical north. 



According to Inö the mean length of one degree of latitude is 

 28.2 ri. From a copy of the standard sliahi used by Inö — the 

 original seems to have been lost by fire — this distance has been 

 estimated as equivalent to 110.7 kilometres. The true value is 111 

 kilometres. The leno-ths of a deo-ree of lono-itude in latitudes 35°, 

 40°, 4-1° are given as 23.1 ri, 21.6 rl and 20.285 ri respectively. 

 Reduced to kilometres, these are 90.7, 84.8 and 79.G6. The true 

 values are 91.08, 85.18, 79.99, ditfering in no case from Inö's values 

 by as much as one-half per cent. 



When we consider the aofe at which Inö besran his scientific 

 career — an ao-e at which most men are thinkin"; of retirini"' from the 

 busy field of life — and when farther we call to mind the rude instru- 

 ments with which he did his work, we cannot but feel that we have 

 here a man worthy of a high place anitjngst the scientific leaders of 

 the last generation. In these days of candid criticism, his work has 

 stood the severest tests and remains a grand monument of his perse- 

 verance, patience and accuracy. His greatness is now fully appreciated, 



