of the Magnetic Needle at Fort Marlborough. 345 
appeared to cover the meridian, through circular holes in the 
bottom of the box. I may venture to assert that the meridian 
was laid off within one minute of a degree, as it.bisected the 
chords of 12 different’ arcs of concentric circles made use of. 
I may also say that the axis, or o° line of the box, was applied 
to the meridian within one minute of true position. In laying 
off the meridian, the operations of two successive days per- 
fectly agreed. — W. or E. put over each observation, indicates 
west or east variation. As bad weather may prevent observ- 
ing at the specified hours at the heads of the columns, the 
hour, if different from 7 A. M. 12 or 5 P. M. or from others 
at the heads of columns, will be marked over those particular 
observations. 
N. B. In the weather columns, to save trouble, F. means 
fair, A. after, R. rainy, N. night, L. lightning, C. cloudy, S. 
sky, T. thunder, m. much, O. overcast, s. serene, W. windy, 
1. little. 
