First Point of Capricorn to Geometry

The winter solstitial point, which the sun enters about the 21st of December.

The autumnal equinoctial point which the sun enters about the 22d of September.

Stars which appear to maintain their places with reference to one another.

High water mark.

The incoming tide; the rising tide.

The old style of diagram compasses printed on charts, having a rose in the middle.

The coming in or the flow of the tide.

Also known as focal length. The distance between the centre of a lens and its focus, or between the object-glass and the image.

To face the body or object when measuring an altitude is known as taking a fore observation. (See Back Observation.)

An old instrument for measuring altitudes at sea.

A consideration belonging to chart sailing by which the ship's place may be fixed after a change of the bearing of the same object, amounting to four compass points. Also known as the Four-Point Problem.

Owing to the obliquity of the ecliptic, the earth's surface is divided into five zones, namely, the torrid, situated between the parallels of 23 deg. 28 min. N. and 23 deg. 28 min. S.; the temperate, extending from the torrid zone to the parallel 66 deg. 32 min. north and south; the frigid, extending from the temperate zones to the poles.

When the whole illuminated face or disc of the moon is turned toward the earth.

An eighth of a mile.

A ship sailing eastward meets the sun in his daily course, and in the circumnavigation of the globe the sun will have crossed the ship's meridian once more often than if the vessel had remained stationary; so it is that an easterly circumnavigator gains a day. On the other hand, a ship sailing westward runs away from the sun in his daily course, and in the circumnavigation of the globe the sun will have crossed the ship's meridian once less often than if she had remained stationary. The date is altered by adding or subtracting one day of the month on crossing the meridian of 180 deg.

The milky way; the luminous band, composed of millions of stars, stretching across the sky.

When the word is used without any qualification it signifies a violent wind.

Referring to the earth; the motion or position of a heavenly body as viewed from the earth-opposed to heliocentric.

The science of conducting a ship by chart and compass from one port to another without recourse to nautical astronomy.

To divide; land surveying; the division of the earth's surface.

Also known as nautical and sea mile; the mean length of a minute of latitude; 6,082.66 feet.

The extremities of the earth's axis.

A branch of mathematics which investigates the measurement of surfaces, solids, angles and lines; the science treating of the properties of magnitude.