ABSOLUTE ATTRACTION OF MATTER. 179 
one mile, and mass equal to that of the earth exerts sufficient attraction to make 
one terrestrial pound weigh 15,659,110 pounds. Hence, that the iron should 
weigh one pound, the large sphere must be diminished in mass so that it will only 
contain the y-gxrgTTTy P^^^ ^^ much matter, wherefore : 6743610190383705901809 
divided by 15,659,110=430,650,924,991,447 tons =861,301,847,982,894,000 
pounds. 
Whence it appears that a sphere containing that number of pounds, whose 
centre is one mile distant from a globe of iron whose diameter is 1.9 inches, 
exerts gravity imparting to it a weight of one pound ; while the small also attracts 
the large sphere with an intensity of a pound, the sum of the attraction of both 
globes being two pounds. But the condition of the problem is that both bodies 
be of equal mass, and still attract each other with the force of a pound. 
It is clear that matter must be taken from the large to the small sphere to 
equalize masses and attraction. Accordingly, let us take one pound from the 
great and add it to the small sphere. Then the small would attract the large 
with a force equal to two pounds, and vice versa ; because by a law of nature we 
know that action and reaction are equal and opposite. Both globes would develop 
an energy of four pounds, which is foreign to the problem. Looking into this 
question closely, we see that if we remove matter from one point to another, its 
attraction on its original position is lessened in the ratio of the square of the 
distance. 
Since in this case distance is a constant, gravity is unable to vary from that 
cause ; hence it must vary in the ratio oi square root of mass. Therefore we must 
extract the square root of 861,301,847,982,794,000 which is 928,063,494 pounds 
or 464,032 tons. Two globes in space whose centres are a mile apart, and 
whose inatter if brought to the earth's surface and weighed, would each weigh 
464,032 tons, will attract each other with a force of one pound, the energy of 
both spheres being two pounds : a pine stick one mile long capable of sustaining 
a weight of two pounds would if placed between them prevent their approach. 
We may be surprised that such vast masses only a mile distant, should develop 
such weak force in view of the colossal power demonstrated in relation to solar 
attraction on the earth, in the June (1883) number of this Revievi^. We therein 
demonstrated that the Sun exerts upon the earth an attractive energy of over 
4,000 quadrillion tons! Surprise, however, will disappear when the immense 
mass of the Sun is considered. 
Of course, the words ton and pound are here used relatively to the earth; 
for the whole sphere, which on the earth's surface would weigh 464,032 tons, 
* weighs ' only one pound when isolated in space as in the problem. Here is a 
table of diameters of globes of several kinds of matter to contain 464,032 tons if 
weighed on scales on the surface of the earth. 
VII- 12 
