ANALYSIS OF BRITISH AND FOREIGN SALT. $$$ 



evaporated to dryness, gave the weight of the earthy mu- 

 riates, which hcd been extracted by alcohol*. 



(B. a.) The dry mass thus obtained might consist either 

 ©f muriate of magnesia, or muriate of lime, or of both. 

 An aliquot part, therefore, was dissolved, separately, for the 

 purpose of assaying it by the usual tests. Sometimes, as in 

 the case of the earthy muriates procured from sea salt, mu- 

 riate of magnesia alone was indicated, and any farther pro- 

 cess was rendered unnecessary. Muriate of lime was in no 

 instance found uncombined; but in the majority of cases 

 (as in the earthy muriates obtained from Cheshire salt) was 

 mixed with muriate of magnesia. 



(B. b.) To the solution of the two earthy muriates was 

 added fully saturated carbonate Of ammonia, which has the 

 property of throwing down lime in combination with carbo- 

 nic acid, but has no effect on thejiiuriate of magnesia at or- 

 dinary temperatures. The solution of the latter salt, along 

 •with that of the excess of carbonate of ammonia, was there- 

 fore separated by filtration J and to the filtered liquor a so- 

 lution of phosphate of soda was added, according to the 

 formula of Dr. Wollastonf. 



(B.C.) By direct experiments I had learned, that 100 

 grains of muriate of magnesia, when thus decomposed by 

 carbonate of ammonia, conjoined with phosphate of soda, 

 give 15t grains Of insoluble ammoniaco-magriesian phos- 

 phate dried at about 90° of Fahrenheit. Hence it was easy, 

 from the weight of the precipitate, to calculate how much 

 of the former salt was contained in the mixture of muriate 



* By the analysis of artificial mixtures of pure muriate of soda with Full amount 

 the earthy muriates in known quantities, I afterward found, that the of the earthy 

 full amount of the earthy muriates was not ascertained in this wav of muriates 6 lV< * n 

 proceeding. The deficiency of the latter salts was about one sixth -, t0 ° sma,I » 

 hut as the en-our must necessarily have been the same in all, it does 

 not affect the comparison of different varieties of salt, as to their pro- 

 portion of this v iugredient. If the numbers in the 5th column of the 

 table (iudicatins; the total earthy muriates) be increased in the propor- 

 tion of six to five, we shall then obtain the true quantities iu each va- 

 riety of salt. 



t Sec Dr. Marcet's analysis of the Brighton Chalybeate, published 

 in the last edition of Saunders ou Mineral Waters. 



Ts of 



