252 



MAGNETIC OBSERVATIONS ON THE BOUNDARY LINE 



From the preceding data we first deduce the moment of inertia, jS", of tlie magnet and its 



4 



attachments^ by the equation K 



K 



J2 



r ^2 



T 



23 



where T^ and T are the terms of one vibra- 



tion with and without the inertia ring^ corrected for torsion^ and reduced to the temperature 

 of experiments without the ring, and obtain the following values : 



At Initial Point, 



Carrizalilloj 



Espia, 



Los NogaleSj 



Mean^ 



K 



2.669 

 2.680 

 2.659 

 2.668 



2.669 



From 



X 



TO 

 X 



the values of ratio of m, the magnetic 

 of the earth's form^ hy the expression 



h 



Initial Point, 



Carrizalillo^ 

 San Luis, 



Los Nogales, 



m 

 X 



64° 



0.04'77, temp. 52° 



0.0481, " 



0.0476, « 



0.0466, " 



65 



82 



Computing for the same stations the product m X 



T^K 



7p2~, where T is corrected for tor- 



sion, and reduced to the temperature of the corresponding deflections, and eliminating X, we 

 get the following values of m. 



Station. 



Date. 



771 



Initial Point 



Carrizalillo 



San Luis 



Los Nogales 



Temperature. 



1 



reduced to 66". 



52 





0.2947 



64 





0.2949 



65 





0.2981 



82 





0.2929 



Although the difference in these values of m may he in a great measure due to errors of 



gnetism 



stations 



a uniform rate of change during the intervals. 



Computing, lastly, m X for each of the stations, and dividing by m determined in the 

 manner indicated and reduced to the temperature of the vibrations, we obtain the values of X 

 given in the subjoined table, which exhibits collectively the results obtained. 



General table of results. 



Station. 



Latitude 



Initial Point 



Carrizalillo 



Espia....» 



6jo del Perro.... 

 San Luis Springs, 

 Sdn Bernardino., 



Sama Cmz River 

 Los Nogales. ... 



« / 

 31 47 



31 51 



31 21 

 31 21 

 31 20 

 31 20 

 31 16 

 31 21 



Longitude 



Declination 

 east. 



106 28 



107 56 



107 56 



108 20' 

 lOa 48 



109 U 



110 31 



no 51 



11 55 

 13 3 



12 5 

 11 58 

 11 45 



11 45 



12 13 

 11 45 



Dip. 



58 39 

 58 31 

 57 59 

 57 28 

 57 37 

 57 19 

 57 28 

 57 13 



Horizontal 

 intensity. 



Total intensity 



6.202 



f 



11.92 



6.125 



11.73 



6 242 



11,77 



6.156 



11.45 



6.265 



11.70 



6.252 



11.58 



6.169 



11.47 



^ 



6.262 



11.56 



