O. T. Sherman— Observations made in Davis Strait. 51 
At Kidluset, lat. 70° 10’, long. 58° 0’, August 25th, 1880, 
we observed a dip Sarit’: 8, and total force 125435. These 
are probably not affected by local influence. 
he Gulnare was a wooden ship with iron frame. She had 
seen many years’ service in the waters of New Foundland, but 
during the winter before the expedition sailed, had been almost 
entirely rebuilt. She was swung at Hampton Roads, on June 
23d, 1880. The observations discussed by the method of least 
squares give the value of the ship’s force to head, , to 
starboard, —0-7845. Three days after, the salt seck the en- 
gineer had allowed to collect in ‘the, boiler reached a thickness 
of several inches and the fire boxes collapsed. ‘These were re- 
placed at St. Johns and for ten days and nights the iron in that 
part of the ship was again subjected to peas: The a 
was again swung at St. Johns. The value of the ship’s 
force reduced, after Evans, by the least ath are force to 
head, —1-916, to starboard, —0:2599, to nadir, —0-4081. On 
August 30th, ‘the values were, force to head, al ‘46299, to star- 
board, —0'83918. On October 5th, the values became to head, 
=" 9971, to starboard, —1°4525, to nadir, —0°3907. A change 
I should be loath to accept were it not thrust upon me by the 
facts of navigation. The swing of October 5th was necessita- 
ted by the discrepancy between the observed and calculated 
courses. It was our custom at sunrise or sunset to observe the 
angle between the sun’s limb and the line of the ship’s keel, 
noting at the same time the ship’s heel and course by the dis- 
turbed compass. These observations served at the time to cor- 
rect our course. Several of these have been again employed to 
give us the declinations at the place of observation. The ship’s 
forces for the date were obtained by simple interpolation from 
the values above given. These connected with the soft iron 
coefficients give us readily the values of the semi-circular varia- 
tion. These, finally, we have placed in the exact expression 
AC+Ba/—C* A+B? 
A? B? 
sin .o = 
which is readily deduced from Evans’ well known formula. 
A,B C are here easily calculated functions of the semi- 
circular and quadrantal coefficients, and the ship’s apparent 
is f 0° E 180° E., the sign — for the remaining 
readings. The values obtained in this way are as follows: 
2B. N W. Hour, p.m, Declination. 
peg 5, 1880, 62°30’ 51°45’ 8 23 N. 57° 42’ W. 
September 10, 6T 6! 58° 307 6 43 N. 70° 59” W. 
September 14, 50° 20’... 6" 2G"... 6. 3 N, 67° 29” W. 
