The Book of Stars: Being a Simple Explanation of the Stars and Their Uses to Boy Life

by A. Frederick Collins

Tangent. [See Appendix B].

Tangent line. [See Appendix B].

Telegraph code. The alphabet of dots and dashes.

Test. To try out. To examine, compare or make an experiment which will give a needed proof.

Theory. [See Idea].

Thumb tack. A short, thin, sharp-pointed tack with a large flat head which permits it to be easily pushed into a board with the thumb. It is used by draftsmen for fastening paper to drawing boards.

Tilting. Leaning from a vertical or plumb line. The axis of the Earth is tilted from the perpendicular 23½ degrees; this throws its equator out of plane with that of the sun, and the circle through the Earth that is in plane with the Sun is called the ecliptic.

Transparent. Said of any substance through which light can pass easily. Anything that may be seen through.

Twinkle. To blink. To flash with varying brightness. The twinkling of stars is caused by the atmosphere.

Uniform. Being the same all through or all along.