LIU. 
OBSERVATIONS ON THE 
' 
MAGNETIC DIP AND DECLINATION 
075 
Observations on the Dip of the magnetic needle made in the plane of the magnetic meridian, and also in 
various azimuths, at every 10°, from 0° to 90°, (by turning the vernier of the upper azimuth plate from the 
magnetic north round to the magnetic west,) made with Major Graham’s dip instrument, by Gambey of Paris. 
Sration.—The astronomical observatory of the Boundary Survey, at Rouse’s Point, state of New York, in Latitude 
45° 00’ 28”, N.; Longitude 4h. 53m. 25s. west of Greenwich. 
Opservers.—Major J. D. Graham and Lieutenant A. W. Whipple, United States Corps of Topographical Engineers. 
2 3 ‘ 
Magnetic | No, 
Mean solar timejazimuth of} of 
Date. | of observation, | plane of | Nee- 
dip-cirele.| dle. 
1845, 
Oct.15,| 04.38. p.m} 0°& 180°} 1 
« «1 1h,4ddm., p.m.| 0°& 180°} 2 
Oot.16, 1 1h.U2m., Am] 0°S& 180° 2 
0 
Oct.16,| 8h.05m., a.m./10°S& 190°) 1 
« 6 | Oh.03m., a.m.}20°& 2007 1 
“  @ \10h.01m., a.m./B0°& 2102) 1 
«© 110R.55m,, a.m.}40°8& 2207 1 
«6 )11h.46mm.,, a.M.|50°& 2307) 1 
«“ & | [h.04m.,, p.m./60°& 2407 1 
« «| Qh,380m,, p.ms!70°& 2509) 1 
« & | 3h. 32m, P.m.)80°& 2607) 1 
© 18, 3hif Berane Peo. 90°dee7 0" it 
5 
Polarity 
of 
marked 
end of 
needle, 
CALLED YA 
|NZnAang 
ZZnuzsn 
ww]. 
R 
(number of observations, packers) +a 
[Zune Zzongse 
Dip, by two hundred 
“VOL. IX, ie 
Peer pi a7 HA’ 2 
1/1 Ba M. 120° °& 200° 2 
‘ 1a eee en m9 8210 2 
4 ha area 9 
‘. ri ose ra ip °& 930°! 2 
OTT) as 35 Mhy Pe M. GG 240°] 2 
«48; 1 14 i 
¢ ia ate y Po PK 2 250°} 2 
. nf dh gal 8078260"), 2 
18 Ate PM 9986270"). 1 
and fifty-six 
in colimn three, and reduced, by computation to the pl une of the mé gnetic meridian, ‘ 
PANYSNZHOPZHSWYSNBZHOA 
BAA PCEOAPE AEP APA MPAA AAA 
S) 
Dip observed in the plane of the magnetic meridian, by a mean of the results of 
i Peay ’ a 
observations on needle No.2, observed in the various azimuths 
6 ve a8 9 _ae ly aac dye 13 14 
ae See = eS 8 ee | Excess of | : : : 
computed | Dip reduced | No. 
Dip observed over ob- | to plane of | of 
in azimuth Dip in Computed |served dipithe magneticjobser- 
by each azimuth by dipin in various | meridian by | va- | Thermo- | Barom, Remarks. 
needle. observation, | azimuth. | azimuths, }each needle, |tions.| meter. eter. 
s09Q/ IN, Weather clear 
sthntgr: ; 76°39'.998 76° 39'.998 | 32 | 43°.1 | 30.21G6jand : se N.W 
40/56 § wind during the 
O98 VST laine 90 8A O97 [Observations of, 
76°37/,9] 7693965 76° 40.84 | 64 43°.1 30.221 both needles on 
76°49’. 91 loco sey, : Ba6 Sie Moret: 
ii 1 3 52! 30.096] Cloudy, stron: | 
the two needles, | 
» pee tart fein hisnnis' ordi oe SHoinenas boimued? 
Bats Neeis igo: i [dori i Ty tf. ote Pt <2 
76°62’. 84 76° 52/1 76°52’, 14 0" 4 76° 40’ 36 32 Qn0 & 2f.9rA! * 
76°5) 36 16° 62's 7 +0704 | 76 F 32 30°.5 | 30,350) Weather clear; 
aig) x r 
77°26) 47 6 apes Bh | eee Hoan docodihind an cael A fresh S, W. 
7°! 3078 779° 28.62 7792707] —17.55 176° 42’.06 | 32 | 33°.2 | 30.850) wind during 
78°26/.09 oO arr ar redo8 ror 1 ee lero w4rse 9 aro © est ee! the observa- 
78004", 03 7B° 257,06 o 24,23) —0’.83 |76° 417138 | 32 35°.2 | 30.350) tions this day. 
rpad’an ¢(70° 42.95 79°42791) —0".04 |I76° 407.46 | 82} 97° | 30.950 
79°44’ .50 fe ott uJ is =U « 0 4 On o¢ OUD | 
o99r | ; ‘ r 
arora og ¢ (S12 20.59 81°20".55| 07.04 |76° 40°46 | 32] 38°5 | 30.350 
B3n 18 20  la30 1.4/.60 nie -0/.13 |76° 40.17 | 32} 419.95 | 30.350 
83°15 51.65 § Be f [ee 13] OLE f 32 41°20 | 30.300 
85924'.97 2 Igo o¥.78 'g5°92",09| 1.69 [76° 45/13 | 32} 43° | 30.350 
85099'59 ¢ [P22 + ise we QU) Oe é ole Om 30.d0 
fe} , 56 ’ 
jp gn Risr9 aor [87°38.G7]—1'73. |76° 49.85 | 92] 44° | 30.347 
89°59.25 ‘ wee | 
ONS 2 lage 5944s 90°00" |}0'.52 | 92) 55°.7. | 30.340 
89°59,.70 4 | : | 
: 4 i . ‘ 
Dip, by two hundred and fifty-six observations on needle No. 1, observed in the various azimuths stated 
in column three, and reduced by computation to the sri of the oltre, oe meridian, . . 76° 42.45) 
EU re bet en vsyor fas [i tte. [aul7O| Clear; Boab 
[7625 544.43 ' SR 76°50 © 39/07 | ois ; 52°.5. louie W. Sak cal 
V7°Sd 87 7) sac wer 6 lseeue? wo anrFa | On |b atc | SUdguiie tri 
ly7ogor.00 ¢(@ ee atB ered 76° 40'.54 | 32/5 5905 30.090 Cloudy; stiong| 
IZ8°R1s 2B en mQoar or 199 ep 99 oni |§ 49° 30,170/south wind on! 
F3004'59 § [78° 22.00 [789M .23}--1'.33 176° 88.18 | 32/2 540 TSo‘ooo the Teh 
79°38/ 56) lec reaere ‘Fie wip deh e ee (one 30.170 
jocqar yy ¢ [79° 407.63. |79°42.91]-4-27.88 |]76° 37.51 | 32 Fi 54° {30,090 /D°- 
BLO] 97,55 ¥ , i ere ‘ r | 50° | 
seein 81°'20'.53 /81°20'.55} + 0"02 “|%6° 40.48 | 32 F ee ony KH Do. 
a’, 12 50 
GS OO8 Pong) aor” hunoy areal nero retare ag Lt SOR 30.172) | 
Oo 14rs RQ) 0 Be oO RA AO r) | OUTS | 
3013/8] ¢ eo” Ab (88° L4.734.0'.52 176° 8942 | 32 2 54°.75 | 30.08 gq|Do- 
B5°23509 Flas gare: lonooer nt aa BO Aaron || Q5 | § 8126 + BOA! 
35929734 ¢ 05° 2321 [85°22".00) —1/.12 as oe pried 
197°37".8 %O AQr wOnaray an leno anew ‘ 6 730.172) 
\37 tat : 87° 38'.01 (87°3367) +0'.66 176°. 36474 | 32 1} 562 139) o7a|D° 
(90°00 eS ey i : 56°.5 (Cloudy; strong 
lo poring 20° 00-59 90°00" | —0'.59 32 § 562 30:070 south, wind. 
stated 
STE UST 39'.52) 
