152 A. TANAKADATE AND H. NAGAOKA. 



expected, since in the previous survey we had tried to station our- 

 selves in places which were as far as possible from buildings and hills. 

 Warned now by this experience, we left a wooden post with the short 

 inscription, " MtlMMll^,'' îind the date, at each place of observjition, 

 while further we give (1^1. XV) some topographical details of the locali- 

 ties, as was done by Lamont, hoping tliereby to save much time and 

 labour and to give much certainty in identifying the places in future. 



The four stations, Nagahama, Obama, Shioya, and Isshiki (Kami- 

 yashiro, in previous reports), are almost identical with the former 

 spots, i. e.y are within a few metres. In Nagoya, the Normal School 

 of the province has since been built on the site of the former station, 

 and we were obliged to have our new station a little to the east, that 

 is, in the back part of the recreation ground. Here we made observa- 

 tions of dip in four places in different quarters of our tent, to see if 

 the new building, though of wood, had any disturbing effect, and as 

 the results agreed within reasonable limits, we assumed that it had 

 not caused any sensible magnetic disturbance. This way of taking 

 the dip at several points in vicinity was carried out in nearly 

 all stations where local disturbance was feared. In Shimizu, a coal 

 depot had been built on the site of our previous station, and the pre- 

 sent determination was made in a place about 100 metres to tlie 

 north-west along the shore. Numazu and Hamamatsu are new ad- 

 ditional stations. 



We further took some of the soil from the station and measured 

 its magnetic permeability. This was done by measuring the magnetic 

 moment in known field. The field was given ])y a solenoid of 39.1 

 cm. length, uniformly wound with No. 13 copper wire, to 13.7 turns 

 per cm. in 6 layers. In order to eliminate the solenoid effect, it was 

 placed in vertical position, and the magnetometer stood 5.2 cm. west 

 of the middle point of the solenoid ; there the direction of the field 



