for eliminating the Weights of Mixed Bases. 189 



The following combinations have been chosen as the most 

 likely to come under the notice of the practical chemist: — 



Potash and soda combined with sulphuric acid ; sodium and 

 magnesium with chlorine ; sodium and calcium with chlorine ; 

 lime and magnesia with carbonic acid. 



The equivalents adopted by Brande have been used in the 

 calculation. 



Carbonic acid ... 22 Magnesium 12 



Chlorine 36 Potash 48 



Sulphuric acid ... 40 Soda 32 



Calcium 20 Potassium 40 



Lime 28 Sodium 24 



1 . When potash and soda exist in combination with sul- 

 phuric acid, the weight of mixed sulphates being known, and 

 also the weight of acid with which they are combined, to as- 

 certain the weight of each base present. 



Rule. — Multiply the whole weight of material experimented 

 on by 15; from the product subtract 27 times the weight of 

 the acid in combination, and divide the remainder by 5, the 

 quotient will be the weight of potash : b being the weight of 

 material experimented on, and a the known weight of acid, 

 the rule stands thus : — 



15 b — 27 a ., . ,. c l n 

 == the weight of potash. 



The whole weight of acid and the weight of potash being as- 

 certained, the weight of soda is of course at once known by 

 subtracting the weight of acid and potash from that of the 

 whole material experimented on. 



2. When magnesium and sodium exist in combination with 

 chlorine, the whole weight of the chlorine in combination be- 

 ing known, to ascertain the weight of each base. 



Rule. — Multiply the whole weight of material experimented 

 on by 6, from the product subtract 8 times the weight of the 

 chlorine, and divide the remainder by 3, the quotient will be 

 the weight of the sodium : — 



= weight of the sodium. 



3 h 



3. When sodium and calcium exist in combination with 

 chlorine, the weight of chlorine being known, to ascertain 

 that of each base. 



Rule. — Multiply the whole weight of material experimented 



on by 18; from the product subtract 28 times the weight of 



chlorine, and divide the remainder by 3 ; the quotient will be 



the weight of the sodium : — 



18 6 — 28 a . i ; f i- 

 = weight of sodium. 



