[See larger version]If the sea, whipping in huge waves against the fury of a typhoon, were to become on the instant rocks, it would be as this. There are heights and crevasses, hills and gulches, crests and hollows, little caves and crannies, where quail and snakes and cotton-tails and jack-rabbits, lizards and coyotes, creatures of desolation and the barrens, hide and scamper in and out. It is an impregnable stronghold, not for armies, because they could not find shelter, but for savages that can scatter like the quail themselves, and writhe on their bellies into the coyotes' own holes.Chemistry also received valuable extensions of its field. Dr. John Mayow published new facts respecting nitre, and on the phenomena of respiration and combustion, as revealed by experiments on this and other substances. At the commencement of the eighteenth century Stahl, a German chemist, propounded his theory of phlogiston as the principle of combustion, which was only exploded by the further discoveries of Dr. Black, Cavendish, and Priestley. Soon after, Dr. Hales threw new light on a?riform bodies, or, as they are now termed, gases; and finally, Dr. Black demonstrated the presence of a gas in magnesia, lime, and the alkalies, which had long before been noticed by Van Helmont, but had been forgotten. This was then termed fixed air, but has now acquired the name of carbonic acid gas, or carbon dioxide. At the end of this period chemistry was extensively studied, and was rapidly revealing its secrets.