Dr. Ure on Muriatic Add, &c. 287 



agitation was employed during the mixture. In 24 hours the 

 supernatant liquid, having become quite limpid, was tested, 

 and found to contain redundant muriate. Small quantities of a 

 very dilute solution of nitrate of silver were progressively added 

 with much agitation, till the clear supernatant liquid was found 

 free from every vestige of chlorine. Nor did muriate of soda 

 shew in it any trace of silver. The total quantity of silver ex- 

 pended to produce this effect was 138.75 grains. This experi- 

 ment was repeated on different quantities, and with a variation 

 in the mode of mixture, but still the same proportion obtained 

 in the result. From the quantity of salt and of silver in their 

 respective solutions, and from the delicacy of my balance, I 

 could add either ingredient to the mixture within ^^^o of a grain. 

 In three experiments, however, in which I used sea salt, re- 

 crystallized with care in regular cubes, I obtained anomalous 

 results, in consequence of minute portions of adhering muriates 

 of potash or lime. From such salt the prime,equi valent of silver 

 appeared to be at different times 13.73, 13.75, and 13.7. It 

 is the tendency of the slightest admixture of these salts, or of 

 sulphate of soda, to lower the apparent atomic weight of silver. 

 If therefore the prime equivalentof chloride of sodium be called 

 4.5 chlorine +3 sodium =7.5, then we must infer from the 

 above experiments that the prime equivalent of silver is 13.875 ; 

 or, taking the proportional weight of hydrogen in water as the 

 radix of the equivalent scale, chloride of sodium will become 

 60, and silver 111 : or, in volume on Sir H. Davy's plan, 120 

 and 222. 



The same solution of silver was used for determining the 

 quantity of chlorine in liquid muriatic acid, having found by 

 experience that its saturation by carbonate of potash, soda, or 

 lime, and evaporation of the chlorides, did not afford results of 

 the minute and consistent accuracy, required by the theory of 

 equivalents. Liquid acid having the specific gravity of 1.200, 

 was diluted with 9 times its weight of water, when its density 

 at 60° Fahr. became 1.020. On this dilute acid I made many 

 experiments with the nitrate of silver, and satisfied myself at 

 last that 1000 grains of it were equivalent to 122] grains of 



