MAGNETIC OBSERVATIONS MADE AT PANAMA. 15 



Results from the Observations of April 2d. 



1st mean, 18 00 47 



2d " 18 00 26 



Mean reading face east, . 18 00 36 



" " west, 17 53 49 



Reading of azimuth circle when reduced to true meridian, . . . . . • 17 57 12.5 



" " " the instrument is in the magnetic meridian, . . . 11 05 36 



Magnetic declination deduced from observations on Polaris, April 2d, 1849, . . . 6 51 36.5 



Results for Magnetic Declination at Panama. 



For March 21st, 1849, 6 63 59 



28th, " 6 48 26 



For April 2d, " 6 51 36 



Final result for the declination of the magnetic needle at Panama, April, 1849, east of north, 6 54 37 



Computation of the Preceding Observations for the Intensity of the Magnetic Force 



T/ I sin V 



^ = sill VI * 



Mr. Fox observed with this instrument upon needles A, B, and C, at Falmouth, 

 England, September, 1^44, and at the temperature of 60^ obtained an intensity of 

 1,000. 



Major Graham and Mr. W. C. Bond observed with the same instrument upon 

 needles A, B, and C, and obtained the following results, which are uncorrected for 

 difference of temperature : — 



1844, December 30th. Temperature -|-39°.5, needle B with weight 3 grs. gave an intensity = 1.2963 



" " " " " " 3.5 " " = 1.2961 



<( 5. « ^ ii "3 " " = 1.2900 



C( « (C (( (( CC Q ^ (( (t 1 OfiQ 



« « " " " 2 deflectors " " rr 1.3014 



1845, January 2d. Temperature +36°, needle A with weight 3.5 grs. gave an intensity = 1.2870 



" " " C " 2.5 " " = 1.2940 



" " " " " 3 « u _ 1,2986 



1845, January 3d. Temperature +13° to 19°, needle C with weight 2.5 grs. gave an intensity := 1.30106 

 " " " " 3 ii i> _ 1.30230 



« 26° " " 3.5 " " = 1.31200 



