OBSEEVATIONS ON 



Dip. 



Cm <o 



ill 



Epoch of 

 commencing 

 vibration, 

 hrs. min. sec. 



Duration ^ . 

 of 500 g. 1 

 Tibra- g -g 

 tiona. ^ '^ 



Calculated 

 duration 

 at 60°. 



Square of the 

 preceding. 



Horizon- Total in- 

 al inten- tensity : 

 sity. hor. be- 

 ing 1000. 



Total inten- 

 sity : that at 

 Cincinnati 

 = 1000. 



139. Wheeling Hill, Va.— Lat. 40° 08' N. Long. 80° 47' W. AprU 30, 1845. 



72° 13' 45" 

 Var. 2 04 B. 



4 

 5 

 6 



3 52 56.6 P 



4 21 04.0 

 4 51 00.4 



1159.6 



1408.8 

 1404.4 



78.0 

 79.0 

 78.0 



1156.25 

 1406.80 

 1402.63 



13369140625 



19793113344 



19673709169 



Mean 



922.3 

 917.1 

 915.1 

 918.2 



3007 



1007 



140. Pittsburg, Pa.— Lat. 40° 26' N. Long. 79° 58' W. May 3, 1845. 



72° 46' 45" 

 Var. 33 04 W. 



4 

 5 

 6 



4 02 57.6 P 



4 29 00.8 



5 13 00.8 



1178.0 

 1432.0 

 1428.8 



74.0 

 72.0 

 71.5 



1176.93 

 1430.80 

 1427.35 



13851642249 



20471886400 



20373280225 



Mean 



890.2 



886.7 

 883.9 

 886.9 



2993.7 



1003.4 



141. Alleghany Summit, Pa.— Lat. 40° 27' N. Long. 78° 10' "W. May 5, 1845. 



72° 27' 05" 



5 

 6 



11 43 04.4 A 



12 43 04.0 P 



1418.4 

 1412.4 



58 

 60 



1418.3 

 1412.4 



20115748900 



19948737600 



Mean 



902.41 

 902.75 

 902.58 



2993.2 



1002.5 



142. Cambridge, Mass.— Lat. 42° 22' 15". Long. 71° 7' 21". June 2, 1845. 



74° 19' 26" 

 Var. 9 32 00 W. 



4 

 5 

 6 



2 58 20 P 



3 34 00.8 



4 07 04.0 



1244.0 

 1612.0 

 1508.4 



87.0 

 87.0 

 87.0 



1242.7 



1509.15 



1504.8 



15443032900 



22775337225 



22644230400 



Mean 



798.48 

 797.03 

 790.87 

 795.46 



2944.1 



985.99 



143. Portland, Maine.— Lat. 43° 41' N. Long. 70° 20' 30". June 4, 1845. 



75° 13' 10" 

 Var. 11 28 20 W. 



4 



5 11 01.8 P 



1277.2 



79.5 



1275.5 



16269002500 



755.95 







Portland Maine.— F. 0. J. Smith. June 5, 1845. 





5 

 6 



12 59 00.0 P 

 1 31 01.2 



1555.6 

 1548.0 



82.0 

 82.0 



1553.2 

 1545.0 



2412330240C 



2387025000C 



Mean 



752.47 

 754.44 

 753.46 



2955.0 



989.66 



REMARKS. 



139. Wheeling Hill, Va. — On the hill, immediately back of the town. Geology: sandstone and 

 shales of the coal-formation. Cloudy, threatening to rain. 



140. Pittsburg, Pa.— Locality : "Whale's back." Geology: a hill of shale belonging to the coal- 

 formation. 



141. Alleghany Summit, Pa. — Geology : sandstone and shale of the coal-formation. 



142. Cambridge, Mass.— Within the new magnetical observatory of Harvard University, about one 

 mile northwardly from the locality of the experiments of 1841. Geology : deep diluvium, superimposed 

 on gneiss rocks. 



143. Portland, Maine. — Geology: gneiss rock, traversed by veins of granite. Soil thin and wet. 

 Clear, with some very slight showers. 



