erroneous notions, adopted too slightly, even by physicians, about material differences between one spring and the other.
The Carlsbad salt (sulfate of soda), extracted since 1708, on the advice of Gottfried Berger, physician to Augustus I, king of Poland and elector of Saxony, at the expense of much fuel, is obtained, since Becher recommanded it, by the mere evaporation of the mineral water. A number of kettles, filled with it, are dept in the same water. That water is constantly renewed by streams of the Sprudel, in the vicinity of which that simple and cheap operation can be seen by any one passing near it. The residuum is freed from its calcareous parts by a second operation in larger vessels, and in a cooler place, where the crystals form themselves.
The Carlbad salt, a revenue of some importance to the town, is often prescribed to drinkers, to assist the purgative effect of the waters; and many provide themselves with one or two pounds of it, to be used, if necessary, after their departure. The salt is sold, under public authority, in boxes of various size, with the town seal. The usual dose is from two to four drachms, dissolved in water.
Various experiments and calculations have been made, to ascertain the quantity of sulfate and carbonate of soda, which the Sprudel alone, by its various orifices, might produce. The apparatus used hitherto for that measurement, was no doubt very imperfect, but a mere view of the abundant fountain will
