206 AN ANALYSIS 



S 



grains of muriate of magnesia, and 45 grains of sulphate of 

 lime *. Reducing them to English weights, they are equal, in 

 a pint of water, to, muriate of soda 241 grains, muriate of mag- 

 nesia 65.5, sulphate of lime 8. This, however, is with regard 

 to water from the Canaries, containing 1 part of saline matter 

 in about 23^ of water. Reducing it to the proportion of the 

 water of our shores, that of about 1 to 30, the proportions will 

 be, muriate of soda 186.5, muriate of magnesia 51, sulphate of 

 lime 6 = 243.5 grains. 



Bergman's analysis is evidently incorrect in the omission of 

 sulphate of magnesia, which every other chemist has obtained, 

 and which is known to be extracted even on a large scale. 

 And, what is singular, this did not arise from his not being 

 aware that it might be present. On the contrary, he made an 

 experiment to discover it ; and even now, in reviewing his me- 

 thod, it is not apparent how he had been deceived. He eva- 

 porated to dryness, and treated the dry residuum with alcohol, 

 by which he found muriate of magnesia to be dissolved ; he 

 then washed the residual matter, consisting chiefly of muriate 

 of soda, with a small quantity of warm water, by which, as he 

 remarked, if any sulphate of magnesia were present, it ought to 

 have been dissolved. But this water shewed no signs of the 

 presence of this salt, either in taste or by precipitation, and 

 contained nothing but a small portion of common salt. Now 

 unquestionably, in this way, sulphate of magnesia ought to 

 have been discovered ; or if it should be supposed that it does 

 not originally exist, but that sulphate of soda is the primary 

 ingredient, still the method employed was equally proper to 

 discover this latter salt. The only supposition that can be 

 made is, that, in the first step of the analysis, a very weak alco- 

 hol 



* Bergman's Essays, vol. i. p. 230. 



