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OBSERVATIONS ON THE MAGNETIC DIP, &C, 
THE FOLLOWING OBSERVATIONS WERE MADE EXPRESSLY TO DETERMINE SOME OF THE LAWS OF 
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123) April 30,Snake Hill, - - = = 40° 43" | 74° 06’ |73°12267, 864.18) 1002.72 |Top of the hill. 'Trappean. 
“a “ 6s 72 3620 | 880.72) 987.06 |Bottom, west side. 
“6 “ “ 72 27 22 | 895.87; 996.19 Bottom, east side. 
May 2, |Fort Lee, New York,- 40 51 | 74 01 /72 2800) 883.02]. 982.43. |North part of Fill, station 1. 
se . ol 72 47 00 | 878.00} 994.26 South promontory, top, 2. 
“6 66 66 72 51 00 | 905.63) 1029.82 |Top, extreme verge, 3. 
* w ‘6 6 Not taken! 895.24 Station 4. 
“6 “ “ 72 38.00 | 881.59} 992.24 |Bottomof hill,& brink of Hudson. 
“6 &“ “« 72 39:15 | 884.27) 994.13 |Inasandy plain, 3 mile from hill. 
June.9, |Patterson, New Jersey, | 40 56 |'74 10 |75 0030] 768.41] 995.17 Top of Garret Rock. Trap. 
+ 10, = - 73 55 54 | 830.21) 1005.46 |Top of trap hill. 
“6 6 66 72.1724 | 900.88] 992.64 |Bottom of hill of trap. 
6“ 66 “ “ 72 58 869.711 995.72  |[n a sandy area—no trap, 
LOCAL ATTRACTION :— 
ERRATA IN THE PRECEDING PAPER. 
Page 286, last line, for “recorded,” read reckoned. 
oe 
“cc 
291, eighth line from the bottom, for “ bluff or cliff limestone,” read bluff of cliff limestone. 
293, about the middle of the page, for “chest,” read chert. 
294, in “23, Dayton, Ohio,”’ seventh column of the table, the decimal point is one place too far to the 
right, thus: for “9511,” read 951.1, and so down the column: and in the eighth column of the same 
table, for ** 298.71,’’ read 2987.1. 
307, in the fourth column of table 78, for “138.0,” read 1380. 
309, twenty-second line from top, for “ temperature,” read intensity. 
309, table at bottom of the page, heading of 9th column, for “horizontal intensity,” read Total intensity 
that at Cincinnati being 1000. 
311, fifteenth line from bottom, for “as follows,” read as above. 
315, twenty-second line from top, for “ subsequent,’’ read subjacent, 
316, 317, and 318, in the heading of the ninth or last column of the tables, for “ Total intensity, hori- 
zontal being 1000,” read Total intensity, that at Cincinnati being 1000. 
