That is the way in which deposits of salt are being now produced on the world's surface, in preparation for that man of the future who, as we learn from a duly constituted authority, is to be hairless, toothless, web-footed, and far too respectable ever to be funny. Man of the present derives his existing salt-supply chiefly from beds of rock-salt similarly laid down against his expected appearance some hundred thousand aeons or so ago. (An aeon is a very convenient geological unit indeed to reckon by; as nobody has any idea how long it is, they can't carp at you for a matter of an aeon or two one way or the other.) Rock-salt is found in most parts of the world, in beds of very various ages. The great Salt Range of the Punjaub is probably the earliest in date of all salt deposits; it was laid down at the bottom of some very ancient Asiatic Mediterranean, whose last shrunken remnant covered the upper basin of the Indus and its tributaries during the Silurian age. Europe had then hardly begun to be; and England was probably still covered from end to end by the primaeval ocean. From this very primitive salt deposit the greater part of India and Central Asia is still supplied; and the Indian Government makes a pretty penny out of the dues in the shape of the justly detested salt-tax--a tax especially odious because it wrings the fraction of a farthing even from those unhappy agricultural labourers who have never tasted ghee with their rice. The thickness of the beds in each salt deposit of course depends entirely upon the area of the original sea or salt-lake, and the length of time during which the evaporation went on. Sometimes we may get a mere film of salt; sometimes a solid bed six hundred feet thick. Perfectly pure rock-salt is colourless and transparent; but one doesn't often find it pure. Alas for a degenerate world! even in its original site, Nature herself has taken the trouble to adulterate it beforehand. (If she hadn't done so, one may be perfectly sure that commercial enterprise would have proved equal to the occasion in the long run.) But the adulteration hasn't spoilt the beauty of the salt; on the contrary, it serves, like rouge, to give a fine fresh colour where none existed. When iron is the chief colouring matter, rock-salt assumes a beautiful clear red tint; in other cases it is emerald green or pale blue. As a rule, salt is prepared from it for table by a regular process; but it has become a fad of late with a few people to put crystals of native rock-salt on their tables; and they decidedly look very pretty, and have a certain distinctive flavour of their own that is not unpleasant.