What ... Photographs Reveal

Perhaps the aoat notable of theae celestial photograpks, ia the direct light that it throws tipon the nebular hypothesis, is Mr. Roberts' üready famous picture of the Androineda nébula. Nobody can look upon the vast nebnlous spirala that this photograph reveáis, surrounding i great central condensa tion, andhowhere and there a brighter knotiwhere a satellite of the hue focal ïnass in in process of formation, without feeling that Laplace and Kant were not very far astray in their guess as to the mode of formation of the solar system. But although stars in abundante are scattered over and around the Andromeda nsbula, there is little in their apIearance to snggest' a connection between tliera and the nebnla. It is different with the ne bules in the Pleiades and in Orion. In the wonderful photographs of the Pleiades by the Henry brothers, of Paris, one not only sees masses of nebulons matter clinging, so to speak, to some of the more conspicuous stars, but in one place a. long, straight, narrow strip of nebnla bas stars dotted along its whole length, like dianaonds strung upon a ribbon. It becomes more difficult to resist the conclusión that in this strange nebuloua streak, with its starry file, we possess an indication of the mode of origin of the many curious streams and chains of stare with which the heavens abound when we look at another amazing ro-elation of celestial photography. I refer to Professor Pickering's photoi-aph of Orion, taken with a portrait lens from a