350 OBSERVATIONS ON THE MAGNETIC DIP AND DECLINATION. 
OBSERVATIONS FOR THE DIP OF THE MAGNETIC NEEDLE, WITH INSTRUMENT BY GAMBEY, 
OF PARIS. 
1841, June 5th.— Washington City, D. C. Same position as on the Ath, viz., under an 
elm-tree which is on the south margin of the northern middle avenue or gravelled 
walk, running east and west through this garden. 
| 
No. of | Polarityof| Face of Marked Meansolartime North end of Neodle South end of Needle} Mean of both ends Attached ‘Name | 
Necdfes‘markedend|Instrument| side  |.f observation) _—_reads_ eid ___of Needle. _/Thermometer,}. of «| 
of Needle. of Needle. | H. M. Deg.|Mins.fTenths. Deg.|Mins.& 1 enths,|Deg.|Mins.gTenths,| (Fahrenheit,) ee 
1 N | E E 7.30 a.m.| 71 . 18 Peet 71. 19.5 “93° a | 
«“ «“ «“ «“ Wt a6 71.93 71°. 21,5 3 
“ Ls WwW WwW 7.40 39 be OL 70. 35 70. 58 74 § 
«“ “ “ «“ 71. 02 70 . 56 70. 59 So 
6 id WwW E 7,50 71.30 (eal 71. 28.5 74 fo 
“ “ u 71. 31 71. 24 TL 27.0 - 
* ee ae WwW 8.00 70.51 70 . 55.5 70. 53.2 75 = 
bie ee | hss ” 70. 51 70. 55.5 70. 53.2 s 
1 Ss E E 8.20 70. 51 70. 56 70. 53.5 76 | 
« “ “ “ 70. 51 70 . 56 70. 53.5 3 
“ « WwW Ww 8.30 71.42 71. 38 71. 40 ie. & 
eé a és & 71.43 71. 38 71. 40.5 o 
= 7 WwW E 8.40 id ae) 71. 08 71. 10.2 78 a 
- 4 - a 71. 13.5 71. 08 71. 10.7 oa 
6 = E WwW 8.50 71 . 23.5 TL ed 71. 25.2 79 = 
" sag = 71 . 23.5 71 ~«. 27.5 71. 25.5 = 
The position of Mr. Nicollet’s instrument is seventy feet in a direction west and per- 
pendicular to the magnetic meridian from my instrument. He is going on with his 
observations simultaneously with mine. 
Needle No. 1 gives, with marked end north, . . . . . +. . « » ., 71° 10'.05 
with morte #Oc sou 2S Se BP 88 
Dip, by thirty-two observations on needle No.1, . © 2 1. e . . . . TP 18",72 
1841, June 5th.— Washington City, D. C. Same position. 
2 N E E 9.35 a.m.| 70. 47 70 . 50.5 WO. 48.7 — 82° g 
“ «“ “ «“ 70.47 70.51 70.49 3 
“ «“ Ww WwW 9.55 71.41 71, 85 71. 38 84 g 
“ “ “ “ 71.40 Wis 84 Te 87 o 
“ «“ Ww E_ | 10.00 #1. 01 70 . 56 70 . 58.5 86 qa 
“ «“ “ «“ W1 . 02.5 70. 56.5 70. 59.5 es 
" ¥ E WwW | 10.08 71. 28 G17 88 M1 480.5 86 “ss 
4 ¥ . és 71. 28.5 71. 92.5 71. 30.5 s 
2 s E E 10,25 72 @ilo VE ..20 7117.5 86° FI 
« «“ « «“ TiN TS os We) spr kee sg 
“ «“ Ww W | 10.35 71. 01.5 70. 55 70. 57.7 86 g 
« « “ “ 71. 00.5 70. 55 70 . 57.2 & 
‘ a WwW E_ | 10.40 71. 32.5 71. 26 71 . 29.2 86 a 
«“ «“ «“ «“ TE 92:5 7126 #1. 29.2 los 
“ ‘“ E W | 10.45 70. 44.5 70.48 70 . 46.2 87 oy 
“ «“ «“ «“ 70. 43.7 70 . 48.5 70. 46.1 Ss 
