98 



RECORD AND RESULTS OF 



ExPEEiMENTS oj? VIBRATIONS, continued. Temperature 74° Fah. 



No. of vibration. 



Right to Left. 



Time 



of 200 double 



vibrations 





200 



12" 45" 56^0 





25"- 



06". 5 







201 



46 03.7 







06.5 







202 



11.1 







06.3 







203 



18.8 







06.5 





Set 4. 



204 



26.2 







06.2 





Time of a double vibration 



205 



33.8 







06.4 





7^5316 



.206 



41.3 







06.3 







207 



48.8 







06.3 







208 



56.2 







06.1 







209 



04.0 







06.3 







210 



11.4 







06.2 







Arc 250 and 340 Mean, 



25~ 



06.33 







Time of 2 vibrations . 







7.5312 





Correction for rate 









—0.0206 





By sets 3 and 4 . 









7.5106 weight 4 





By sets 1 and 2 . 









7.5083 weight 1 





2y = 









7.5101 at 740.4 Fah. 





T' = 









3.7550 



" 



And when corrected for" torsion and referred to temperature 72°.75 IgT^ = 1.14976. 

 Observations for Torsion. 



Tor. cir. 





Scale. 





Differences. 



69° 



298.6 and 



308.8 





♦ 









6.8 



159 



308 





313 



17.0 



339 



235 





302 



10.0 



69 



295 





312 







Mean 



(4) 





. 8.45 =8'. 57 



Experiments of Deflection. July 3, 1860. 

 Magnet Z 6 deflecting; Z 1 suspended. Distance 1.0 foot. Temperature, 73°. 

 Circle reading. 



s. 



end east 



N. 



" west 



s. 



" " 



N. 



" east 



N. 



end east 



S. 



" west 



S. 



" east 



1450 54' 

 145 45 

 126 40 

 126 23 



Distance 1.3 foot. 

 131 43 00 

 131 48 20 

 140 34 00 

 140 34 00 



54' 40" 



45 40 



41 20 



25 00 



Temperature, 72°. 5, 

 43 40 



Setl. 

 145° 50' 05" 



126 32 00 



49 



00 



35 



00 



35 



00 



131 

 140 



190 18' 05" 

 9 39 02 = 



48 30 



24 15 =u 



From Ig mX = 0.04019 

 and Ig '^,= 8.92999 



771 



X 



we find X = 3.60T 



and m = 0.3070 at 73° 



' For comparison the following four values were taken from the Coast Survey Report of 1861, 

 Appendix No. 22. Cambridge t = 42° 23' and % = 71° 07' 



No. 

 1 

 2 

 3 

 4 

 5 



Year. 

 1842.5 

 1842.8 

 1845.5 

 1856.6 

 1860.6 



Observers. 



Locke 



Lefroy 



Locke 



Friesach 



Sonntag 



X 



3.657 

 3.665 

 3.618 

 3.542 

 3.607 



