366 OBSERVATIONS ON THE MAGNETIC DIP AND DECLINATION. 
Cloudy; wind north-east; nearly calm. Light rain and mist during part of the obser- 
vations on needle No. 2. 
The point of observation is the intersection of the eastern shore of the Madawaska 
with the north shore of the St. John River. 
XXXVI. 1844,—May 2d. Portsmouth, New Hampshire. 
On Jamaica Island, near its north-western shore, in the hay-field of Mr. Isaias Preble. 
Latitude 43° 04’ 56”, N.; Longitude 70° 43’ 56”, W. 
NEEDLE No. I. 
anced on Seadeas. Cnereptin. ‘Temperature, Dip observed. 
S 16 Oh. 16m., P.M. 73°.5 74° 49.62 
N 16 0 59 ee 74 74° 45/59 
Dip by thirty-two observations on needle No.1, . . . . . . 74° 47/6 
NEEDLE No. 2. 
Ss 16 lh. 42m., P.M. 72°.5 74° 47/93 
N 16 2 eI % 73 74° 47.53 
Dip, by thirty-two observations on needle No.2, . . . 74° 47/73 
Dip, by a mean of sixty-four observations on needles Nos. 1 and 2, 74° 47.66 
Sky somewhat overcast. Fresh breeze from west-south-west. 
Norre.—In the observations at this and the succeeding four stations at and near Portsmouth, I was assisted by 
Lieutenant Whipple, of the Corps of Topographical Engineers attached to the survey for the defences of the 
harbour. Iam indebted to him for the latitudes and longitudes of the actual positions of observation, which were 
derived by him from an accurate triangulation made to connect them all, in latitude and longitude, with the 
Unitarian stone Church, whose position was taken as given in the American Almanac, as in latitude 43°04’ 35”, N.; 
and longitude 70° 45’ 50’, W. of Greenwich. 
XXXVI. 1844,—May 2d. Portsmouth, New Hampshire. 
The point of observation is eighty feet on a magnetic course of 8. 68° 30’ W. from the 
northern extremity of Captain Stansbury’s base line for the trigonometrical survey of 
the harbour of Portsmouth, and is in Latitude 43° 02’ 59”, N.; Longitude 70° 43’ 36”, W. 
NEEDLE No. 1. 
N a 36 5h. 03m., P.M. 75°.B 74° 35/25 
Ss 16 5 32 & 73.5 74° 39'.48 
Dip, by thirty-two observations on needle No.1, . . . . . . 74° 37/36 
NEEDLE No. 2. 
N 16 5h. 52m., P.M. 73° 74° 38/.97 
Ss 16 6 To ee 72 74° 38'.43 
Dip, by thirty-two observations on needle No.2, . . : eT 
Dip, by a mean of sixty-four observations on needles Nos. 1 1a 2,. 74° 38’.03 
Weather fair. Strong wind from the west-south-west. 
XXXVIII. 1844,—May 3d. Portsmouth, New Hampshire. 
The point of observation is in Mr. Robert Shelliby’s pasture field. The instrument 
stands on a knoll twenty paces from a lonely black wild cherry tree, two fect in diameter 
