AND THE INTENSITY OF MAGNETICAL FORCE. 293 
Locality, on the alluvion of the river, near a town called Winchester. High cliff 
limestone bluffs at a moderate distance from the valley of the stream. Cloudy, smoky, 
calm. Barometer 749.4 mill.; thermometer 16. cent. 
16. Prairie du Chien, W. T., Latitude 48° 01’, N.; Longitude 91° 08’, W.; October 24, 1839. 
Duration Calculated , ck. | Tete intensity, 
Dip. No.of |Epochofcommencing} of 500 |'Tempe-| duration Square of the Horizontal | Total intensity, ‘that at Cincin- 
Needle. Vibrations. Vibrations,| rature. at 60°, preceding. intensity. |Hor. being 1000. jnati being 1000. 
3 11h.28m.028.4 | 1320. | 65° |1319.62|1741396.9444| 876.34 | 3045.44 | 1018.73 
73°16'35" 
Declination, 9° 5’, east, (surveyors. ) 
Although noted at Prairie du Chien, the experiments were made at the ferry, on the 
side of the Mississippi opposite the prairie, on a low alluvion, surrounded very closely 
by precipitous bluffs of sandstone and limestone, geologically lower than the cliff, and 
scarcely fossiliferous, but still horizontally stratified, 
17. Blue Mound, W. 'T’., Latitude 43° 01’, N.; Longitude 89° 54’, W.; October 29, 1839. 
73°41’ | 3 | 1h,557.088,2 P| 1335.6] 46° |1336.7 | 1786766.89| 854.00] 3038.54 | 1017.43 
Declination, 8° 38’, east, (surveyors. ) 
The above locality is in the bed of a streamlet west of the West Mound. ‘The Blue 
Mounds are conical outliers of the cliff limestone, three hundred feet of their upper part 
being silicious chest, horizontally stratified. 'The base contains lead ore, ‘They rest on 
sandstone, and are one thousand feet above the Wisconsin river. 
18, Madison, W. 'T’., Latitude 43° 05’, N.; Longitude 89° 41’, W.; November 2, 1839. 
74°03'30"| 1 |104.20m.00s.4 (1666.8 |54°1 [1667.2 |2779555.84 | 851.79 | 
2 | Oo d5 08.2 2|1643.2 is 1647.17/2713169.0089, 851.32 | 
3 | 8 39 00 0 {1836.4 |44 5 11837.5 |1788906.25 | 852,06 | 
| Mean, 851.72 |' 3102.25 | 1037.76 
Declination, 7° 30’, east, (surveyors. ) 
Locality, near the capitol, say four hundred yards from it. ‘The rocks are limestone, 
horizontally stratified, but scarcely fossiliferous. No height around much above the site 
of the observations. 
19. Mineral Point, W. 'T., Latitude 42° 50’, N.; Longitude 90° 10’, W.; November 5, 1839, 
73°20'37"| 1 |12h.07m,035.2 [1646.8 | 48° |1650.1512722995.0225] 869.45 | | 
2 ha 46 OL 6 6278 44 |1631.37/2661368.0769| 867.89 | | 
3 |11 86 00 4 (1824.4 | 44 [1825,63/1'757294.8969) 868.47 | 
| | Mean,! 868.60) 3030.40 | 1013.70 
! 
Declination, 8° 40’, east, (surveyors. ) 
Locality, a moderately deep valley, one mile east of town, with no bluffs or peculiar 
elevation near. Geology, cliff limestone, horizontally stratified, and containing lead ore, 
and some copper in the underlying rock. 
At 6h. a.m. Barometer 720.0 millimeters; thermometer 6. cent. Wind north. 
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