294 OBSERVATIONS ON THE MAGNETIC DIP, 
20. Cincinnati, Latitude 39° 06’, N.; Longitude, 84° 22’, W.; September 24, 1840. 
‘ Duration Calculated Total intensity, 
Dip. No. of | Epoch of commencing} of 500 |Tempe-| duration Square of the | Horizontal) Total intensity, |that at Cincin- 
Needle. Vibrations. Vibrations.| rature. at 60°. Preceding. intensity. | Hor. being 1000. /nati being 1000, 
70°29'11” 11h.19m.00s.6 |1542.8 \66°4 1541.6 |2377147.24 | 995.94 
1 
Zo 112 00°: 08 .& 0 11524.6:)70 1522.4 |2317701.76 996.58 
a 12 80 Ol 2. 1287,2.170 1236.48/1528932.25 998.12 
Mean,| 996.88} 2984.40 998.31 
| 
| 
| 
Ill. SERIES, 1840, OHIO, KENTUCKY, AND INDIANA. 
21. Cincinnati, August 18, 1840, Latitude 39° 06’, N.; Longitude 84° 22’, W. 
70°27'26 1 {11h.09m.01s.2 A]1542. [78° |1538.67/2367505.3689 
2 112 13 O1 6 P/L524. (78 75/1519.8 |23809792.04 
3 1 06 O1 6 {1235.34|78 5 |1235.34)1526064.9156 
Mean, 1000; 2989.4 1000. 
Done at the most usual locality for Cincinnati—Mr. Longworth’s garden, under the 
bank descending towards Deer Creek. Coefficients for the several needles as follows, 
namely, No. 1, 00012.; No. 2, 000145.; No. 3, 000058. 
22. Hamilton, Ohio, Latitude 39° 23’, N.; Longitude 84° 32’, W.; August 20, 1840. 
70° 58’ | 1 |10h.42m.02s. A] 1560.8) 80° |1557.05/2424404.70 | 976.55 
2 ;11 18 038 6 | 1540.4; 85 |1535.0 |2356225, 980.24 
3 |11 57 O1 4 1250.6) 82 |1249.0 |1560001. 978.02 
Mean,| 978.338 | 2999.9 1003.50 
23. Dayton, Ohio, Latitude 39° 44’, N.; Longitude 84° 17’, W.; August 21, 1840. 
71°22’ { 1 | 2h.14m.00s.0 P| 1578.8|83°5 |1574.34|2478546.4356| 9511. | 
2 |2 53 02 2 | 1561.4/84 0 |1555.77/2420420.2929| 9543. 
3 | 3 27 00 0 | 1264. [84 0 |1262.24]1593249.8176| 9577. 
Mean,| 9544.0 | 298.71 999.15 
Locality, the broad alluvion of Dayton, underlaid with gravel. Rocks in situ, the 
blue horizontal limestone, the same as at Cincinnati. Meteorology, clear with a mixture 
of cirri and cumuli. Some distant thunder, but no rain. Wind south-east, gentle. 
Evening clear, with some meteors. 
24, Piqua, Ohio, Latitude 40° 06’, N.; Longitude 84° 13' 5”, W.; August 22, 1840. 
71°35'50"| 1 4h.41m.00s.8 P|1585.2 | 80° [1581.4 |2500825.96 946.60 
2 5 26 59 6 {1568.0 | 79 {1563.7 |2445157.69 944,60 
3 6 06 00 0 {1270.0 | 70 |1269.26)1602094,76 947.20 
Mean,| 946.10 2997.3 1002.60 
Geology, horizontal cliff limestone, country level. 
25. Lebanon, Ohio, Latitude 39° 26', N.; Longitude 84° 06’, W.; August 24, 1840. 
"71°02'45"| 1 | 4h.5377.00s.4 P|1563.2 |77°5 |1560. |2433600. 972.84 
2 15 34 00 8 {1545.6 |75 5 |1542,13/2378164.9369| 971.25 
Mean,| 972.04 | 2993.63 1001.07 
Horizontally stratified blue limestone, near the surface. 
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