_Fixed stars_--held by astronomers to be suns--are known from the planetary stars by their perpetual "twinkling," and by their being, apparently, always in the same position relative to each other. Now, while the number of stars to be seen in the heavens by the naked eye on a clear night does not exceed about 3,000 in each,--the northern and southern hemispheres,--yet Herschel, Olmsted, and other examiners tell us that by the aid of the telescope, many millions stand out in brilliant array--so vast their number that they cannot be correctly computed, but are supposed to be at least _one hundred millions_. Prof. Olmsted declares it fully demonstrated that "_the fixed stars are suns_," and, with other astronomers, argues the fair probability of many of them being of far greater magnitude than our own sun. Dr. Wollaston, a distinguished English philosopher, attempted to estimate the magnitude of certain of the fixed stars from the light which they afforded. "By means of an accurate _photometer_ (an instrument for measuring the relative intensities of light), he compares the light of Sirius with that of the sun. He next computed how far the sun must be removed from us in order to appear no brighter than Sirius. He found it would require to be _one hundred and forty-one thousand times_ its present distance, and even at that great distance Sirius must give out twice as much light as the sun, or that, in point of splendor, Sirius must be at least equal to two suns." "But," adds Prof. Olmsted, "as _Sirius_ is more than _two hundred thousand times_ as far off as the sun, he has rendered it probable that its light is equal to that of _fourteen suns_." (We wish you to bear these facts in mind, they will serve you when we come to speak of the magnitude of our own sun.) But let us follow Prof. Olmsted a little farther. He says, "We have already seen that they are large bodies; that they are immensely farther off than the farthest planet; that they shine by their own light; in short, that their appearance is, in all respects, the same as the Sun would exhibit if removed to the region of the stars. Hence, we infer that they are bodies of the same kind with the Sun.