A. Because it supplies it with _moisture_ for a considerable time; which penetrates slowly into the soil, and insinuates itself through every clod, ridge, and furrow. Q. _Why is there NO SNOW in SUMMER time?_ A. No snow reaches the general surface of the earth in summer time, because the _heat of the earth_ melts it in its descent. Q. _Why are some MOUNTAINS ALWAYS COVERED with SNOW?_ A. 1st--Because the _air is more rarefied_; and rarefied air _abstracts heat_ which it holds in a _latent state_: 2ndly--As the mountain top is _not surrounded by earth_ to radiate heat into the air; therefore, the snow is _not melted_ in its descent, but falls on the mountain, and lies there. Q. _Why is SNOW WHITE?_ A. Snow is formed of an infinite number of very minute crystals and prisms, which reflect all the colours of the rays of light; and these colours _uniting_ before they meet the eye, cause snow to appear white. Q. _What is HAIL?_ A. Rain, which has passed in its descent _through some cold bed of air_, and has been frozen into drops of ice. Q. _Why is ONE bed of air COLDER than another?_ A. This is frequently caused by _electricity_ in the air, _unequally distributed_. Q. _Why is HAIL frequently accompanied with THUNDER and LIGHTNING?_ A. 1st--Because the _congelation of water into hail_ disturbs the electricity of the air: and 2ndly--The _friction_ (produced by the fall of hail) excites it still more. Q. _Why does HAIL fall generally in SUMMER and AUTUMN?_ A. 1st--Because the _air is more highly electrified_ in summer and autumn: and 2ndly--The vapours (being rarefied) ascend to the more elevated regions, where the _cold is greater_ than it is nearer the earth. Q. _What TWO things are essential to cause HAIL?_ A. Two _strata of clouds_ having _opposite electricities_, and _two currents of wind_. The _lower cloud_ (being negative) is the one _precipitated_. Q. _What is RAIN?_ A. The vapour of the clouds or air _condensed_, and precipitated to the earth. Q. _Why is the vapour of the air or clouds PRECIPITATED?_ A. When the air is _saturated with vapour_, if a cold current _condenses_ it, it is no longer _able to hold all its vapour_ in solution, and some of it is squeezed out, and falls as rain. Q. _Why does RAIN fall in DROPS?_ A. The vapoury particles in their descent _attract each other_; and those which are sufficiently near, _unite_ and form into a drop. Q. _Why does not the COLD of NIGHT ALWAYS cause rain?_ A. When the air is not _near saturation_ (although condensed by the chill of evening), it will still be able to hold its vapour in solution. Q. _Why does a PASSING CLOUD often drop RAIN?_ A. Because the cloud (travelling about on the wind) comes into contact with _something that chills it_; and its vapour being squeezed out, _falls to the earth as rain_. Q. _Why are RAIN-DROPS sometimes much LARGER than at OTHER times?_