40 



erroneous notions, adopted too slightly., even by phy- 

 sicians, about material differences between one spring 

 and the other. 



The Carlsbad salt (\sulfate of soda), extracted 

 since 1708, on the advice of Gottfried Berger, phy- 

 sician 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 evapora- 

 tion 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 resi- 

 duum 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 car- 

 bonate of soda, which the Sprudel alone, by its 

 various orifices, might produce. The apparatus used 

 hitherto for that measurement, was no doubt very im- 

 perfect, but a mere view of the abundant fountain will 



