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OBSERVATIONS ON THE MAGNETIC DIP AND DECLINATION. 357 
I was joined in the observations at this station by Professor Alexander D. Bache, 
President of Girard College. The needles were read by us alternately. The initials in 
the last column will show the observations made by each observer. 
Raining all the time we were observing with needle No. 1. 
Needle No. 1, gives, with marked end north, Pe Seog 2 gle 6 
wit markec end south % ©." oes, eviagaanoy 14S ges 
Dip, by forty-eight observations on needle No.1,. . . 2. 2. 0... 0.) 719 85.25 
1841, ane une 14th.—At the Magnetic Observatory of Girard College, Philadelphia. 
rs = ee ow ener an _ SEES ae 
No.of | Polarity of | Face of ZE Marked Rech wotustiel INortti chd ond of Needle |Southe end of Ne edle alt ‘Mean of both ends | Attached Name | 
Needle, markedend|{nstrument,| — side pecbaervelipyy ah ret [ of Needle, Thermometer. ee 
of needle. lew Needle. HH. M, Deg g.{Mins. §Tenths. iPe z[ins. §Tenths.| Deg. .|Mins.§ por nears bine ‘ahrenheit.) Observer. } 
2.) op E E |6.25r.m.| 72.00 2 . 05 72.025 ° | J.D.G.| 
“ « oa ee 72.01 72. 05 72. 08 68°.5 |A.D.B.| 
«| 4 ae ee 72.025 | 72.06 72. 04.2 J.D G.| 
«“ «“ BE | W. |6.30 Tis Bl | 71. 35 Vl. 83 | A.D.B.| 
‘ “ «“ «“ 71.27 i71 32 7. 0s. J. D.G. 
a“ “ Me ALE 71.29 [71 . 84 71. 31.5 A.D.B. | 
“ “ W E |6.84 72 . 20 72.14 72.17 J.D.G.! 
«“ «“ “ «“ 72. 20 72.138 72. 16.5 A.D.B. | 
«“ «“ | 72.20 172.18 72. 16.5 J. DG] 
& ct WwW We-| 0% 87 Th 4% Vi. 88 715. 42.5 A.D.B. | 
“ «“ «“ «“ 71.44 71. 37 71. 40.5 J. D.G.! 
«“ «“ “ «“ 71.45 an . 39 ‘71. 42 A.D.B.| 
Poo oe W |6.57 (72.215 | 72.14 m.17 | 6 Be. 
«“ Ft ae « 72. 23 72.15 72.19 A.D.B.! 
ena eS ck “ 72 . 23 72. 15 72.19 J.D.G. 
«“ ‘2! W | E .|7.00 “1 4g 71.5 A [71.44 | A.D.B. | 
Me se : re 71.47 71.40 71. 43.5 | J.D.G,! 
“ “ | “ «“ 71.48 71. 40 71.44 | A.D.B.| 
‘ «“ E W., 4.7.05 72. 03 Ze, OF 72. 05 J.D.G.| 
«“ aoe ile «“ 72. 04 72. 06 72 . 05 | A.D.B.| 
‘ #00 oa «“ 72. 02 72 . 06 72. 04 J.D.G.| 
or E E sts 20 71, 28 71. 33 71,:.20.5) . |  6%.5 JA.D.B.| 
«“ | “ «“ v6 Pyle 71. 32 71°. 20:6 3 J. D.G.| 
i * Le Oe, 2 PTAs RE oF GR LG). 29,6011 ‘A.D.B.} 
Raining nearly all the time we were observing this day. 
Needle No. 2,.gives, with marked end north, . . . . .:. ... ... 71° §4'.22 
with.matked Gna #outa,. . .... .-« + “mean o@t* Oa.22 
Dip, by forty-eight observations on needle No, 2) vi oe vee gwece 5. 71° 53/72 
Dip, by forty- eight observations on needle No.1, . . . . 71° 55.25 
Magnetic dip at the Magnetical Observatory of Girard College, Philadelphia, 
by ninety-six absor rations on needles Nos. 1 and 2, June 14, 1841,. . . 71° 64’.48 
XTX. Cambridge Observatory, Massachusetts. 
Latitude 42° 22’ 21’.3, N.; Longitude 71° 07’ 37.5, W. 
‘The station occupied was the marble table usually occupied by the variation Transit 
belonging to the Magnetic Department of the Observatory. This is the temporary 
observatory used until the permanent establishment shall be constructed. 
I was joined in these observations by Wm. C, Bond, Esq., Director of the Cambridge 
