16 NA7 URE'STUD Y RE VIEW [17:1— Jan., 1921 



Eclipse of the sun May 26, 1900 



Three stages photographed by Verne Morton 



Eclipses 



One of the best things about sunlight is that whatever it illu- 

 mines casts a shadow ; this would be a monotonous world indeed, 

 without shade to relieve and emphasize the beauty and brilliance 

 of Hght. However, there is one important limitation to shadow, 

 it has to rest upon something in order to become visible. The 

 shadow of the tree rests upon the ground or against a building or 

 some other object ; but if the tree were high up in the sky, we should 

 have to prove it had a shadow by mathematics since there would 

 be no object below it to bring the shadow into visibility. This 

 condition of affairs is what makes an eclipse so very interesting. 

 Our great star, the sun, shines on, day and night illuminating all 

 his other planets and their moons even as he does our earth and our 

 moon; and each one of these spheres, big and little is always one 

 half in the light and one half in the dark, and each of them is 

 casting a cone-shaped shadow, if science is to be trusted, but we 

 are quite unaware of it because there is nothing for the shadow 

 to rest upon so that we can see it. However, occasionally one of 

 these spheres passes between the sun and another sphere and 

 briefly throws its shadow upon it and thus causes us to see it and 

 we call it an eclipse. 



We have two kinds of eclipses, one when the moon passes be- 

 tween the sun and the earth and covers the latter with its shadow, 

 which is called an eclipse of the sun ; the other is when the earth 

 passes between the sun and the moon and throws its shadow upon 

 it, thus causing an eclipse of the moon. 



