70 THE SUN. 



VOLUME OF THE SUX. 



But we have hitherto only spoken of the diameter of the sun ; let us now 

 consider its bulk. When we know the diameters of two globes we can always, 

 by an easy operation of arithmetic, estimate theirbulks. Thus, if one globe have 

 a diameter double another, the bulk of the former will be eight times that of 

 the latter. If the diameter be ten times greater, the bulk will be a thousand 

 fold greater, and so on. Now we know that the diameter of the sun is about 

 one hundred and twelve times greater than that of the earth, from which we 

 infer, by the same principles of arithmetic, that the bulk of the sun must be 

 very nearly one million four hundred thousand times the bulk of the earth. To 

 make a globe like the sun, it would then be necessary to roll one million 

 four hundred thousand globes like the earth into one ! It is found by consid- 

 ering the bulks of the different planets, that if all the planets and satellites in 

 the solar system were moulded into a single globe, that globe would still not 

 exceed the five hundredth part the globe of the sun : in other words, the bulk 

 of the sun is five hundred times greater than the aggregate bulk of all the rest 

 of the bodies of the system. 



WEIGHT OF THE SCX. 



The astronomer, however, is called upon to execute processes more difficult 

 and yet no less indispensable, than the mere measurement of distances and 

 magnitudes. If we desire to know the quantities of matter composing those 

 distant orbs, we must not merely measure their magnitudes and fathom their 

 distances, but we must wing our flight, in imagination, across those vast 'lis- 

 ( tances which separate us from them and weigh their stupendous masses. If 

 ( the popular student finds it difficult to believe and comprehend how we can 

 measure distances and magnitudes such as those of the heavenly bodies, how 

 much more will he be confounded when he is assured that we have at our dis- 

 posal a balance of the most unerring exactitude :'.n which we can place those 

 vast orbs and poise them ! The globe of the sun itself, transcendency greater 

 than the earth and all the planets put together, is weighed with as great relative 

 S precision, as that with which the chemist in his analysis, estimates the weights 

 of the constituents of the bodies which pass under his hands. As the general 



