WATER OF THE DEAD SEA. '^^ 



the 0"136 grains of selenite belonging to 250 grains of the 

 water, yielded 4 814 grains of pure lime — 4*66 grains acid 

 :z:9*48 grains muriate of lime. 



I should not omit mentioiiing, that the method which I 

 used in all my experiments to ascertain the quantity of pure 

 lime in oxalate of lime, consisted in driving off the oxalic 

 acid by a low-red heat, and adding to the calcareous residue, 

 then converted into a subcarbonate, a known quantity of 

 muriatic acid more than sufficient to dissolve the whole 

 lime. A piece of marble of known weight was afterwards 

 added to take up the excess of acid, and from these data 

 the quantity of lime was calculated with great precision. 



8. The clear solution containing nitrate of magnesia, 

 nitrate of soda, and a small excess both of oxalate and mu- 

 riate of ammonia, and amounting in bulk to about 4 ounces, 

 was exposed to the heat of a lamp for concentration ; but in 

 a few minutes the mixture became turbid and began to de- 

 posit a white powder, which, from former observations, I sup- 

 posed to be oxalate of magnesia. 1 o this solution concen- Subcarbonate 

 trated to between 2 and 3 ounces, and still warm, I added of ammonia, 

 carbonate of ammonia with excess of pure ammonia. A 

 considerable precipitation immediately appeared, and the 

 mixture became opaque and milky. The next morning, 

 however, the fluid had become quite transparent, and in- 

 stead of a white impalpable precipitate, I found clusters of 

 perfectly pellucid crystals spread over the bottom of the 

 vessel, with distinct interstices between them. 



This salt was no doubt an ammoniaco-magnesian carbo- 

 nate; and the remaining solution, although still containing, 

 as will presently appear, a vestige of magnesia, was so far 

 free from it, as oot to have its transparency disturbed by 

 caustic potash. These crystals, after being well washed 

 iu distilled water, were exposed to a gentle heat to drive off 

 the ammonia, in consequence of which they crumbled down 

 into a white impalpable powder, exactly resembling common 

 carbonate of magnesia. This powder being then treated, 

 and its quantity estimated, in a way similar to that which 

 had been employed with the lime; and being increased by 

 the addition of about 0'5 of a grain of a similar precipitate 

 (which had escaped the action of the carbonate of ammonia 

 D 2 and 



