MAGNETIC OBSERVATIONS. 



97 



Observations at Cambridge, Mass. July 3, 1860. 



Harvard College Observatory. A. Sonntag, observer. 



Experiments of vibration. Magnet Z 6 suspended. Time noted by sidereal chronometer Bond 



236. Temperature, '76° Fah. 



. of vib'n. 



Left to right. 



No. of vib'n. 



Left to right. 



Time of 60 double 

 vibrations. 









12" 18"5.3=.2 



50 



12" 25°" 0917 



O" 16^5 





1 



19 00.8 



51 



n.i 



16.3 





2 



08.3 



52 



24.8 



16.5 



Setl. 



3 



15.8 



53 



32.2 



16.4 



Time of a double 



4 



23.2 



54 



39.1 



16.5 



vib'n, r.5296 



5 



30.8 



55 



4'?.3 



16.5 





6 



38.2 



56 



54.8 



16.6 





1 



45.8 



5t 



26 02.3 



16.5 





8 



53.3 



58 



09.8 



16.5 





9 



20 00.9 



59 



11.S 



16.4 





10 



08.2 



60 



24.8 



16.6 





Mean . . 6 16.48 



I Arc at commencemeut|^ 150 and 460 

 [^ " .end j 180 420 



No. of vib'n. 



Right to left. 



No. of vib'n. 



Right to left. 



Time of 50 double 

 vibrations. 









12" 20° 49^5 



50 



12" 27'" 06^3 



6" 16'. 8 





1 



57.2 



51 



13.8 



16.6 





2 



21 04.8 



52 



21.2 



16.4 





3 



12.3 



53 



28.8 



16.5 



Set 2. 



4 



20.0- 



54 



36.2 



16.2 



Time of a double 



5 



2T.4 



55 



43.9 



16.5 



vibration 7^5282 



6 



35.0 



56 



51.2 



16.2 





t 



42.5 



57 



59.0 



16.5 





8 



50.1 



58 



28 06.3 



16.2 





9 



57.t 



59 



14.0 



16.3 





10 



22 05.2 



60 



21.5 



16.3 





Mean ... 6 16.41 

 Arc at commencement f 170 and 435") 

 " end 1190 41o| 



Time of 2 vibrations, 7.5289 



Correction for rate, —0.0206 



(By sets 1 and 2), 



7.5083 



Experiments of Vibrations, continued. Temperature, 74° Fah. 



0. of vibration. 





Left to 



right. 





Time of 200 double vibrations. 





200 





12" 43" 



5 9". 3 







25" 



06M 





201 





44 



06.8 









06.0 





202 







14.4 









06.1 





208 







22.7 









06.9 



Set 3. 



204 







29.2 









06.0 



Time of a double vibration 



205 







36.9 









06.1 



7=.5309 



206 







44.3 









06.1 





207 







51.9 









06.1 





208 







59.4 









06.1 





209 





45 



07.0 









06.1 





210 



14.6 

 252 and 338 









06.4 





Arc, 



Mean, 



25^ 



06.18 





13 June, 1865, 

















