THE SUN. 6l 



does upon each individual ton of matter which the earth 

 consists of, it must pull it as if (mind I say as if) it were 

 made up of 360,000 earths. And this is what is meant 

 by saying, that the mass or quantity of gravitating 

 matter constituting the sun is 360,000 times as great as 

 the mass or quantity of such matter in the earth. 



(18.) Thus, now, you see, we have weighed as well as 

 measured the sun, and the comparison of the two results 

 leads to a very remarkable conclusion. In point of size, 

 the globe of the sun, being in diameter no times that of 

 the earth, occupies in bulk the cube of that number, or 

 1,331,000 times the amount of space. The disproportion 

 in bulk, then, is much greater than the disproportion in 

 weight, very nearly four times greater : so that you see, 

 comparatively speaking, and of course on an average of 

 its whole mass, the sun consists of much lighter materials 

 than the earth. And in this respect it agrees with all the 

 four great exterior planets, Jupiter, Saturn, Uranus, and 

 Neptune ; while all the others Mercury, Venus, and 

 Mars agree much more nearly with the earth, and seem 

 to form a quite distinct and separate family. 



(19.) From this calculation of the mass of the sun, and 

 from its diameter, we are enabled to calculate the pres- 

 sure which any heavy body placed on its surface would 

 exercise upon it, or what power it would require to lift 

 it off. It is very nearly thirty times the power required 

 to lift the same mass here on earth. A pound of lead, 

 for instance, transported to the sun's surface, could not 

 be raised from it by an effort short of what would lift 

 thirty pounds here. A man could no more stand 



