NOTES ON SOME CELESTIAL PHOTOGRAPHS. 95 



it is without doubt one of the finest bits of mountain scenery in 

 the moon. Another photograph shows the "Mare Crisium" with 

 the sunlight just at the right angle to show its surrounding moun- 

 tains. This sea measures two hundred and eighty miles one way, 

 by three hundred and fifty the other, and in the photograph the 

 undulations " hill and valley," and the small craters in it are 

 clearly shown. One of the minor ridges runs parallel with the whole 

 length of the western boundary, like an inner range. Another 

 photograph shows the moon eight days old with " Copernicus " 

 and other features very well defined, but on a smaller scale, and 

 still another view brings out conspicuously the markings of full 

 moon. 



Leaving the work done with this new attachment to the Star 

 Camera, I should like to show a fine photograph obtained three 

 days since with the Star Camera. It has, you see, in the centre 

 of a surrounding multitude of stars, (for it takes in a part of the 

 Milky- Way) a small but beautifully defined nebula. I am not yet 

 ready to go fully into detail about this, suffice it to say that this 

 is called the Trifid Nebula, from the fact that three dark lines 

 lead up to a very conspicuous triple star, and has attracted a good 

 deal of attention from Sir J. Herschel and others. The photograph 

 which is beautifully clear, while preserving some of the leading 

 features presented to the eye in the telescope, and recorded by 

 Herschel and others, reveals so many more that the whole aspect 

 is changed. These details are of the same character as those in 

 Eta Argus and others that I have photographed, and are totally 

 different from those which the eye aided by the most powerful 

 telescope can make out. Indeed photography is altering our 

 view of what Nebulae in detail are like, so that in speaking of 

 pictures of Nebulae it is very necessary to say how they were pro- 

 duced. The sensitive film seems to grasp details which the eye 

 -cannot see, and I am disposed to think that this is not owing to 

 the faintness of the light, but to some inherent difference which 

 the Camera can and the eye cannot see. 



