- 11 — 



Xaha. 



MngnetA (;4:£?^y=1.131 



° \\2.<i:D,J 



ai.8131 V 



aoAdW 



B (J-iÄY = 1.2ö78 



The declinations were taken with a declination theodolite of ordinary 

 construction. The diameter of the circle, on Tvhich the needle was mounted, 

 was 14.5 cm. The graduation was only to half-degrees. The circle together 

 with the^telescope was movable about a vertical axis. This motion was effected 

 by a tangent screw, and could be read to Kf by means of a vernier. 



At Kagoshima the direction of north was deduced from time observations 

 combined with azimuth observations of the sun's position. The azimuth of the 

 telescope was successively changed by 10' and the contacts of the sun's disk 

 were observed sis times with the preceeding limb and six times with the suc- 

 ceeding limb. The successive positions of the magnet relatively to the circle, 

 which moved in azimuth with the telescope, were read at intervals. Two such 

 series of observations were taken. The magnetic declinations so obtained 

 are as follows : — 



1st series 3° 20'.5 W 



2nd „ 3° 17'. W 



Mean 3° 18'.7 W. 



At Xaha Mr. Tanakadate from transit observations made meridian 

 marks on two distant objects one to the north and the other to the south. 

 The transit instrument was then dismounted and the theodolite set in its place. 

 The mas'netic declination so observed was : — 



2° 25'.5 W. 



The determinations of the dip were also rough, and were obtained by a 

 comparison of the horizontal and vertical intensities of the magnetic field due 

 to the earth. A solenoid was formed by winding insulated copper wire upon 

 a glass tube 31.5 cm. in length and .9 cm. in diameter. The wire was wound 

 in two layers, the total number of coils being about 1030. The resistance of 

 the wire was 6.07 ohms. Xear one end of this solenoid, which could be fixed 

 either horizontally or vertically, a small-mirror magnetometer was set. To 

 intensify the magnetic field within the solenoid a soft-iron wire of nearly the 

 same length was inserted. When the soft-iron wire was in position and a 

 current flowing through the solenoid, the iron wire was under the influence of 

 two distinct niagnctisatious, that duo to tho earth, and that duo to the current. 

 The strength and the direction of tho current were then adjusted until tho 

 magnetometer deflection was made equal to that which the current in tho sole- 



