What is "inclination of the needle"

Inclination \In`cli*na"tion\, n. [L. inclinatio: cf. F. inclination.]

1. The act of inclining, or state of being inclined; a leaning; as, an inclination of the head.

2. A direction or tendency from the true vertical or horizontal direction; as, the inclination of a column, or of a road bed.

3. A tendency towards another body or point.

4. (Geom.) The angle made by two lines or planes; as, the inclination of the plane of the earth's equator to the plane of the ecliptic is about 23[deg] 28'; the inclination of two rays of light.

5. A leaning or tendency of the mind, feelings, preferences, or will; propensity; a disposition more favorable to one thing than to another; favor; desire; love.

   A mere inclination to a thing is not properly a willing of that thing.
   --South.

   How dost thou find the inclination of the people?
   --Shak.

6. A person or thing loved or admired.
   --Sir W. Temple.

7. (Pharm.) Decantation, or tipping for pouring.

   Inclination compass, an inclinometer.

   Inclination of an orbit (Astron.), the angle which the orbit makes with the ecliptic.

   Inclination of the needle. See Dip of the needle, under Dip.

   Syn: Bent; tendency; proneness; bias; proclivity; propensity; prepossession; predilection; attachment; desire; affection; love. See Bent, and cf. Disposition.