Chap. 46.] VARIOUS KINDS OF NTTBUM. 513 



it is found, but in smaller quantities, and deteriorated with 

 earthy substances, being known there as " agrion." 66 As to 

 that prepared from the burnt wood of the quercus, 67 it never 

 was made to any very great extent, and the manufacture of it 

 lias been long since totally abandoned. Nitrous 68 waters are also 

 found in numerous places, but not sufficiently impregnated to 

 admit of condensation. 69 



The best and most abundant supply is found at Lita3, in 

 Macedonia, where it is known as " Chalastricum :" 70 it is white 

 and pure, and closely resembles salt. In the middle of a cer- 

 tain nitrous lake there, a spring of fresh water issues forth. In 

 this lake the nitrum 71 forms for nine days, about the rising of 

 the Dog-star, and then ceases for the same period, after which 

 it again floats upon the surface, and then again ceases : facts 

 which abundantly prove that it is the peculiar nature of the soil 

 which generates the nitrum, it being very evident that, when 

 the formation is there interrupted, neither the heat of the sun 

 nor the fall of rain is productive of the slightest effect. It 

 is also a truly marvellous fact, that though the spring of fresh 

 water is always uninterruptedly flowing, the waters of the lake 

 never increase or overflow. If it happens to rain on the days 

 during which the nitrum is forming, the result is, that it is 

 rendered additionally salt thereby : the prevalence of north- 

 east winds, too, still more deteriorates its quality, as they have 

 a tendency to stir up the mud at the bottom. Such is the 

 formation of native nitrum. 



In Egypt, again, it is made artificially, and in much greater 

 abundance, but of inferior quality, being tawny and full of 



66 "Wild." 



67 See c. 40 of this Book. He is evidently speaking of a vegetable al- 

 kali here. See Beckmann, Vol. II. pp. 492-3, John's Ed. 



68 Beckmann thinks that these kinds of water were in reality only im- 

 pure and not potable, from their nauseous taste, and that hence they were 

 considered as nitrous. Nitrous water, he remarks, or water containing 

 saltpetre, in all probability, does not exist. Vol. II. pp. 498-9. Bohris 

 Edition. 



69 Or in other words, crystallization. Beckmann remarks that, in re- 

 ference to alkaline water, this is undoubtedly true. Vol. II. p. 499. 



70 From the adjacent town of Chalastra, on the Thermaean Gulf. The 

 site is probably occupied by the modern Kulakia. 



71 Carbonate of soda is found in the mineral waters of Seltzer and 

 Carlsbad, and in the volcanic springs of Iceland, the Geysers, more parti- 

 cularly. 



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