In all there are about 3,000 stars visible to the naked eye in each hemisphere. A three-inch pocket telescope brings about one million into view. The grand and scientifically perfected instruments of our great observatories show incalculable multitudes. Every improvement in light-grasping power brings millions of new stars into the range of instrumental vision and shows the "background" of the sky blazing with the light of eye-invisible suns too far away to be separately distinguished. Great strides are daily being made in stellar photography. Plates are now being attached to the telescopic apparatus whereby luminous heavenly bodies are able to impress their own pictures. Groups of stars are being photographed on one plate. Complete sets of these star photographs are being taken every year, embracing every nook and corner of the celestial sphere and these are carefully compared with one another to find out what changes are going on in the heavens. It will not be long before every star photographically visible to the most powerful telescope will have its present position accurately defined on these photographic charts. When, the sensitized plate is exposed for a considerable time even invisible stars photograph themselves, and in this way a great number of stars have been discovered which no telescope, however powerful, can bring within the range of vision. Tens of thousands of stars have registered themselves thus on a single plate, and on one occasion an impression was obtained on one plate of more than 400,000. Astronomers are of the opinion that for every star visible to the naked eye there are more than 50,000 visible to the camera of the telescope. If this is so, then the number of visible stars exceeds 300,000,000 (three hundred millions). But the picture taking power of the finest photographic lens has a limit; no matter how long the exposure, it cannot penetrate beyond a certain boundary into the vastness of space, and beyond its limits as George Sterling, the Californian poet, says are-- "fires of unrecorded suns That light a heaven not our own." What is the limit? Answer philosopher, answer sage, answer astronomer, and we have the solution of "the riddle of the Universe." As yet the riddle still remains, the veil still hangs between the knowable and the unknowable, between the finite and the infinite. Science stands baffled like a wailing creature outside the walls of knowledge importuning for admission. There is little, in truth no hope at all, that she will ever be allowed to enter, survey all the fields of space and set a limit to their boundaries.