ARTICLE XV. 
OBSERVATIONS OF THE MAGNETIC DIP IN THE UNITED STATES. 
BY PROF. ELIAS LOOMIS. 
In the Transactions of the American Philosophical Society, Vol. VII., pages 1—6, and 
pages 101—111; also, Vol. VIII., pages 65—72, and pages 285—304, I have given nume- 
rous observations on the Dips of the Magnetic Needle, made by myself, in different parts 
of the United States. The following observations were made with the same instrument 
heretofore employed. This instrument was made by Gambey, of Paris, and has two needles. 
In 1841, the axis of one of the needles appears to have sustained some injury, and since 
that time the needle has been entirely discarded, and all the observations have been made 
with the other needle. The mode of observation is the same as has been described in Vol. 
VIL., page 3, of the Transactions of the American Philosophical Society, 
Magnetic Dips at Hudson, Ohio, Lat. 41° 15’, Long. 81° 25’ West. 
Place of observation, magnetic station formerly used. 
DATE. Hour. POLARITY. No. READINGS. Dips. 
1842, May 17. 9—10 A. M. Mark down. 40 G22 462. 
a6 G6 08 Mark up. 40 53.3. 
« “ ate Mean result. - 80 49.3. 
a8 10—11 A. M. Mark up. : 40 53.0. 
oo as 6 Mark down. 40 47.8. 
us fe at Mean result. 80 50.4. 
Mean of both sets of obser. 160 72 49.9. 
1842, Aug. 23. 9—10 A. M. Mark down. 40 72 46.7. 
ab os oG Mark up. 40 51.4. 
Ob ce ab Mean result. 80 49.1. 
_ VOL. XI.—24 
