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 For this purpose the liquid, clarified by subsidence and decantation, was transferred into oblong leaden boilers, about nine feet long, three wide, and nine inches deep. Two-thirds of the length of these boilers were set upon iron plates heated by a fire beneath; the remaining part was supported by flat tiles, and defended from the heat by a solid brick work. As the water evaporates, the Glauber’s salt begins to crystallize. It is swept from time to time to the cool extremity of the boiler, whence it is shovelled into baskets placed over the end of the boiler, that the liquid which drains off may not be lost. The evaporation is continued till feathered crystals of sal-ammoniac begin to appear on the surface. The liquid is then run into coolers, and deposits little else than sal-ammoniac till the temperature sinks to 70°. The crystals must now be removed, that they may not be mixed with the Glauber’s salt, which begins at that temperature to be deposited. The sal-ammoniac thus obtained is first drained in baskets, and then exposed to heat in a kind of oven, till the water of crystallization is driven off. It becomes spongy, friable, of an ash-colour, mixed with small white filaments.

This salt is introduced, while still hot, into globular grey earthen jars, fitted with a cover (with a hole of about half an inch diameter in its centre), luted on with a mixture of clay and horse-dung. These are set in earthen pots over a strong fire, in a furnace of either a circular or oval form, and capable of containing from six to eighteen, surrounded with sand up to the edge of the pot, and also having about 2½ inches of sand on the cover, confined by an iron ring about three inches deep, and two inches less in diameter than the cover, in order that the luting, should it give way, may be repaired without suffering the covers to he cooled by the removal of the sand; for, during the sublimation, their temperature should be about 320°. These earthen vessels may be filled with the dried salt, to within two inches of the top. It may be gently pressed in, but not rammed close. The fire, which has been lighted some time before, is now to be raised gradually till the iron pots are of a pretty strong red heat all round. They are so placed in the furnace, that the upper part is first heated; the bottoms resting on solid brick work. At first, a quantity of aqueous vapour, carrying with it a portion of the salt, escapes through the hole in the cover. The hole must be left open as long as any moisture exhales. This is known by bringing a cold smooth iron plate near the hole, in order to condense the sublimate. When the water is gone, the salt attaches itself to this plate, in the form of a dry semi-transparent crust. The hole is now to be stopped up with lute, and more sand put upon the cover. The heat is to be kept up till it is judged that most of the sal-ammoniac, but not the whole, has sublimed. The time requisite for this depending on the furnace, can only be learned by experience. if the heat be continued too long, the cake of sal-ammoniac acquires a yellow colour, and a scorched, opaque, crackled appearance, which, injuring its saleability, ought to be avoided. When the lute gives way, and requires repairing during the process, the appearance of the cake of sal-ammoniac is injured. On this account, glass vessels would be preferable to those of clay. But, in this country, the expence of glass is so great, on account of the high duty laid upon it, that manufacturers are scarcely able to use it in those cases where the vessels must be broken at the end of every process, as is the case in the sublimation of sal-ammoniac. Aikin’s Dictionary of Chemistry, art. Sal-Ammoniac.

One process more deserves to be mentioned, on account of its ingenuity and simplicity. It is the invention of Mr Astley, who has secured the exclusive privilege by a patent, and has a manufactory at Borrowstowness on the Firth of Forth, and another at Portobello, near Edinburgh. He mixes together animal matters (chiefly woollen rags), with what in Scotland is called spirit of salt. It is the mother ley that remains after all the crystals of common salt that can be got have been separated from sea water. It consists chiefly of muriate of magnesia. This mixture is burnt in furnaces, and the produce received in small chambers placed over the furnaces. This produce contains abundance of sal-ammoniac, which is obtained pure by sublimation. We conceive the theory of this process to be, that carbonate of ammonia is formed by the combustion of the animal matter. This carbonate immediately decomposes the muriate of magnesia, and sal-ammoniac sublimes. In principle, therefore, it does not differ from Baumé’s original process, though, in point of economy, it is probably greatly superior to it. We have little doubt that Baumé’s method yields a greater return from the same quantity of materials; but this is probably much more than counterbalanced by the much greater expence attending his process. Nothing can demonstrate this more clearly than the circumstance that his method was abandoned in France as too expensive, though labour be much cheaper in that country than in this, while Mr Astley manufactures his sal-ammoniac with profit in the neighbourhood of Edinburgh. (.) AMPHIBIA. See in Index to the article . ANA, a Latin plural termination, appropriated to various Collections of the observations and criticisms of eminent characters delivered in conversation, and recorded by their friends, or discovered among their papers after their decease. Though the term Ana is but of modern origin, the species of composition to which it has been applied, is not of such recent date as some persons have imagined. It appears from D’Herbelot’s Bibliotheque Orientale, that, since the earliest periods, the Eastern nations have been in the habit of preserving the maxims of their sages. From them this practice passed to the Greeks and Romans. Plato and Xenophon treasured up and recorded the sayings of their master Socrates. From their example, Arrian, in the concluding books of his Enchiridion, which have not descended to posterity, collected the casual observations which had dropped from Epictetus. The numerous apophthegms scattered in Plutarch, Diogenes Laertius, and other writers, evince that it had been customary in Greece to preserve the ideas Rh