OBSERVATIONS ON THE MAGNETIC DIP AND DECLINATION. sol 
Needle No. 2 gives, with marked.end: notthj: ss. iiec2e0 2 oe ein © oC eaedigs 
with marked end:agigtiye te lsdcme tliw coe b-A ® OF SI 
Dip, by thirty-two observations on needle No.2, .0. 2.0. 4. 2... 70° 10.78 
Dip, by thirty-two observations on needle No.1, 20 2 0s oe os ve a PEP 18472 
1841, June 5th.—Dip, near the centre of the public garden, east of the 
capitol, by a mean of both needles of Gambey,. . ... 2.9. «a. . 71°. 12'.22 
Mr. Nicollet transcribed in my note-book, with his own hand, the result of his obser- 
vations with his own instrument, and requested me, when I reported mine, to report his 
also. They are as follows, viz.: 
OBSERVATIONS FOR THE DIP OF THE MAG ee a NEEDLE, WITH INSTRUMENT BY ROBINSON, 
F LONDON, 
Date and place of observation.—1841, yas 5th.— Washington City. In the public gar- 
den east of the capitol, and occupying a point thirty-nine feet west of the centre of the 
garden, and retell feet west of eee Graham’s instrument. 
No. of | Polarity of ot| Face of |Markedside |e ansolartime! Mean of both e ends as | Attached Name 
Needle,|Marked end)Instrament.| of Needle, Of observation. of Needle, Thermometer, of 
of Needie, | rH, OM. |Deg g.|Mios.§"Tenths. IG ahrenheit. } | Observer. 
| 
1 N E E 7.10a.m.| 71 . 00 | 1ae 
a s W WwW PlectB 
6 6 Ww ™ re, 3 
66 “ Dy Ww 71.18 | a 
es a a Sa En, PON nMtee air oe Ss 
“ “ Ww Ww a1, Be A 
“ " W E via Bs 2 
6 66 E WwW TL G7 — 
1 8 E ee 71.30 Aas 
«“ «“ Ww WwW 71. 05 ey 
“ “ W E 71.41 
uae ek. E W |.8.30 {71.00 an 
a2 ON oe as i Bay OO 2" YO O10 +3 
& & WwW WwW 71.8 79 = 
bi * WwW E Zl, 08.5 2 
“ te E Ww Ti vot ae 
2 Ss i E | 71. 25.5 = ra | 
«“ ts W Ww | 71. 06.5 fon 
“ «“ Ww B | 71°. 80.5 
be : E W  |10.05.-| 70...53.5 84. a 
“ Norg.—Each observation recorded is a mean of three readings of each end of the needle.-—J. N. N.” 
“Having applied the magnets to this needle, intending to reverse the poles, it was 
suspended for observation, when it was found, that, through a mistake in applying the 
magnets, the poles were not reversed.—J. N. Nicon.er.” 
Needle No. 1, with markedend tiorth, gives) -- =. GP 25 
With TOBPReC Co mei, VIVeR, ee a9" 
DD Ry MNO By ye ee 8 ne ee re? 18 19 
“Weather fine; light clouds near the horizon; light north-west wind.” 
VOL, IX.—-92 
