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keep the image in place, just "kissing" the horizon line. Finally, the upward movement of the [sun] ceases, there is a slight period of appent rest, and then it begins to descend toward the W. At that instant the captain says "Eight bells”, which means 12 o'clock noon. It is always noon, as you know, when the sun is at its highest point.

The captain has now found two things. He has found the exact second of noon for his locality, and the index of his sextant tells him just how many degrees above the horizon the sun was at that second. The diagram will make this plain. 

A - Captain

D - Sun

B - Horizon 

C - Zenith - (spot in the heavens which is directly overhead)

The angle C.B.A is a right angle, therefore the arc C.B. Is a quarter circle of 90°. We will suppose the Captain's sextant shows that the arc from the [sun] to the horizon – from D to B - is 40°. Then the distance from [sun] to Z must be the difference between 40° and 90°, which is 50° – savvy?

Consequently, the captain has found the distance of the [sun] from a spot directly overhead him: in other words, has found his distance from the [sun] to be 50°. Suppose his almanac tells him that the [sun] that day was directly over the equator. Then his is 50° from the equator, or in lat. 50°. Suppose that the almanac said he was 10° S the equator. The captain, knowing himself to be somewhere to the north of it, must subtract that 10° from his 50° from the [sun] to get his distance from the equator. That would be put him somewhere on the 40th parallel of latitude. This parallel, as you can see on the chart, passes through N.J. Just south of Sea Girt. But it goes all the way around the world, and, so far, as the latitude is concerned, our captain might be anywhere on it. He must, therefore, out where on that parallel he is; in other words,

(Con’t)