and parts of adjacent States. 363 
Table continued, 
. om 
Stations. iseslsation. Declivatios: ~ Conpenil 
° ° 
Philadelphia, 38 381. | 405 
aston, 3-6 441 ~46 
msport, 3:54 3°16 +23 
Curwinsville, 1°77 151 +16 
-0'83 o'04 ~54 
rie, 0°52 044 +05 
Dunkirk, og 1°29 -23 
Eliicottsville, 2°62 r +40 
ath, Sea a, 3-50 +03 
Silver Lake, 452 466 -08 
The probable error of any single representation is +194. 
The curves of 0°, 
, pass through the following positions: 
tat 41° 00" Lat. 42° 30’ Lat. 39° 30’ 
Long. 80 15 Long. 80 33 Long. 79 54 
7... bet, - 41° 00° Lat. . 42° 30’ Lat. 
Long. 78 07 Long. 78 46 Long. 77 05 
4° Lat. 41°00’ Lat, 42°30’ Lat. 39°30’ 
Long. 75 56 Long. 76 59 Long. 74 17 
These curves have been finally adopted. | 
Distribution of the Magnetic dip, ~ —— of the isoclinal lines, 
for 
‘ en sons more convenient ce oe of the usual analytical 
ression for the representation of the observed dips and for 
the "an pears the stations have been divided into six groups, 
llow 
No. |” Group I. Latitude. | Longitude. Date. Observed dips 
o é o i 
1 | Philadelphia? 39 58-4 | 75100 | Feb, 1842 | 91 571 
2 | Doylestown, 40 18 75 10 July 1841 72/931 
3 | Easton, 40 42 75 15 “ 1841 2 
4 | Reading 40 y 75 55 “ 1840 72 32:2 
5 Pcunaowe. 39 3 75 51 ? Aug. 1840 71 4072 
6 | Baltimore, 39 17°8 76 36°6 «1840 71 33-9 
7 | Washington,‘ 38 53-1 77002 | Sep. 1841 71 15: 
8 | Harrisburg, io 16 76 53 July 1840 72 20° 
9 | Duncan’s Island, 4o 25 77 Of “1840 72 35-0 
to | Near Mercers , 47 Ps f Aug. 1840 Sy 473 
L Mean, 39 571 76 16- 1841-0 | 72 04°4 | 
ao mie? is the mean from groups of December 1840, October 1841, and Au- | 
* This station has been added to the discussion, as we have observations in 1840 
and 1841; see Appendix No. 26, Coast Survey Report of 1858, Mea 2 ‘ip from 
in 1841 Several observers in 1841-0, 71° 183, and in 1e40-5, ate 13’5. Mean, 71° 157-9 
