ON NATURE. 
141 
least neglect occurs, either in the application of too much or too little water; 
and these are evils which cannot always be guarded against, even by those who 
are the most careful. In plants having their roots confined within the limits of 
a garden-pot, and exposed to the sun on the shelf or stage of a greenhouse, and 
watered at certain periods of the day, without much regard either to the state of 
the weather or the degree of their several wants, it is no wonder that when so 
treated, some of them should occasionally appear sickly, and others of them die; 
indeed, it is certainly less to be wondered at than that they should exist at all. 
The chief objection, therefore, to plants being kept in the house in summer is, 
that being exposed to the sun, the earth in the pots becomes dry, and the ex¬ 
tremes of heat and cold, wet and dry, to which the roots are thence subjected, 
cause the plants to assume a brown and unhealthy appearance; and, generally, 
the leaves on the lower branches to fall off. These evils may be effectually pre¬ 
vented by using double pots, as recommended by Mr. Blair, with this modifica¬ 
tion, that his pots being intended for growing marsh or aquatic plants, require to 
be cemented together at the bottom; but for the present purpose, nothing more 
is necessary than that the empty pot, which is intended to form a screen for the 
other which contains the plant, be sufficiently large to receive the latter within it, 
so that the tops of both are nearly on a level. 
Those who cultivate many of the tropical ferns, will also find it of service in 
preserving the delicate roots of these plants from the effects of dry heat.— Mr. 
Marnock. — Gard. Mag. 
Clouds. —The clouds in which the condensed vesicles of vapour are collected, 
are affected by attraction, which draws them towards the mountains, and high¬ 
est points of the surface of the earth. Being collected there, they undergo a 
change, by which they form into drops, and are deposited in the form of rain ; 
and hence by their natural gravitation, they find their way through the pores and 
interstices of the earth, and in channels along its surface, forming in the one 
case, wells and springs in various parts of the earth, where they find a natural 
exit, or where an artificial exit is given to them; and, in the other case, obey¬ 
ing the form of the surface of the country through which they are carried, they 
wiud in narrow channels, first deepening and widening as they proceed, and are 
fed by tributary streams until they form into great rivers, or spread into lakes, 
and at length discharge their waters into the sea.— Lard. Cy. 
Transparency of the Sea. —Times may occur in a long voyage, when on the deep sea, 
the surface may be so still and quiet, that telescopes might enable the eye to penetrate many 
miles down, and bring to our view many of those creatures still living which are supposed to 
have been destroyed, and not to have lived since the creation of man. Over these immense 
plains, lofty mountains, and dense groves, two or three miles from the surface of the sea, far out 
of the reach of winds, storms, and currents, may even now exist those huge snails, the Cornua 
AmmoniSjtheNautilus, with its proper inhabitants, the Megalosaurus, Tctliyosarus Plesiosarus, 
Ornithocephali, Mammoths, &c. &c. All these may, most of them certainly could, live at 
immense depths, and in the dense air, as we know our own toads, frogs, and newts can do. 
No argument against this can be framed, on the fact, that their recent remains are never found 
thrown upon any shores; because the great depth at which they live would render it impossi¬ 
ble for any storm ever to disturb them ; and if the animals lived at the bottom, their remains 
could never rise to the top. through such a prodigious weight of water and of air .—Field 
Naturalist. 
