TRANSLATORY MOTION OF THE SUN.
This phenomenon is the progressive motion of the centre of gravity of the whole solar system in universal space. Its velocity, according to Bessel, is probably four millions of miles daily, in a relative velocity to that of 61 Cygni of at least 3,336,000 miles, or more than double the velocity of the revolution of the earth in her orbit round the sun. This change of the entire solar system would remain unknown to us, if the admirable exactness of our astronomical instruments of measurement, and the advancement recently made in the art of observing, did not cause our progress towards remote stars to be perceptible, like an approximation to the objects of a distant shore in apparent motion. The proper motion of the star 61 Cygni, for instance, is so considerable, that it has amounted to a whole degree in the course of 700 years.—Humboldt’s Cosmos, vol. i.