780. _Why will a towel, the corner of which is dipped in water, become wet far above the water?_
Because the water is conveyed up through the towel, by _capillary attraction_. The atoms of the water are attracted by the _threads of the towel_, and drawn up into the _small spaces between the threads_.
_Capillary._--Resembling a hair, small in diameter.
[Verse: "He stretcheth out the north over the empty place, and hangeth the earth upon nothing."--JOB XXVI.]
781. _Why do small bodies floating upon water move towards larger ones?_
Because the attractive power of a _large body_ is greater than that of _a small one_. As each atom of matter has inherent power of attraction, it follows that a _large aggregation of particles_ must attract in proportion to the number of those particles.
782. _Why do clouds gather around mountain tops?_
Because they are _attracted by the mountains_.
783. _Why would a piece of lead tied to a string, and let down from a church steeple, incline a little from the perpendicular towards the church?_
Because the _masses of stone_ of which the church is built would _attract the lead_.
By observing what is called the _deflection_ of small bodies _when brought within given distances of larger bodies_, the degree of attraction _exercised by the large body upon the smaller one_ becomes known. This attraction of the _large body_ exercised over the _smaller body_ is an opposing influence, _acting against the earth's attraction of the small body_, which is drawn out of its course: it constitutes a _natural balance between the influence of the earth and another body, acting in opposition to it_. Founded upon these, and some other data, man can weigh the earth, and give a morally certain result!
The planets exercise as certain an influence upon each other _as do two pieces of wood floating upon a basin of water_. As the planetary bodies fly through their prescribed orbits, _and approach nearer to, or travel further from, each other_, they are observed to _deviate_ from that course which they must have pursued _but for the increase or the decrease of some influence of attraction_. By making observations _at various times_, and by comparing _a number of results_, it is possible _to weigh any planetary body, however vast, or however distant_.