Vapor. A gas produced from a liquid or a solid and which returns to its original form at ordinary temperatures. See Gas.
Vertical. [See Appendix B].
Vibration. A to-and-fro movement, as the vibration of a particle of matter. A constant to-and-fro movement over the same line.
Visible. That which the eye can see.
Wane. To gradually grow smaller. Said of the Moon.
Wax. To gradually grow larger. Said of the Moon.
Winter Stars. The stars which can best be seen during the winter months.
Wireless Messages. Messages which are sent and received by wireless telegraph stations.
Wireless system. An apparatus for sending and receiving messages by wireless telegraph.
Your meridian. The line running due north and south in the sky directly over your head. A meridian of this kind is called a celestial meridian.