CHLORINE. 83 



We see that the first is a compound of one atom 

 mercury and one atom chlorine, and the second 

 of one atom mercury and two atoms chlorine. 

 Here, as well as with copper, 4'5 represents 

 exactly the weight of an atom of chlorine. 



3. Silver is a metal, the atomic weight . , 



chloride of 



which is 13 tr ?5. Dissolve 13*75 grains of pure silver. 

 silver in nitric acid ; evaporate the solution 

 gently to dryness, and re-dissolve the nitrate 

 of silver in water ; precipitate the silver by 

 pouring into the liquid a solution of 7'5 grains 

 of pure and dry common salt ; collect the pre- 

 cipitate, wash it well, and fuse it on a piece of 

 glass : if the experiment be properly conducted, 

 the chloride of silver, thus obtained, will weigh 

 18*25 grains.* Now, it contains exactly 13*75 

 grains of silver. Hence, it is composed of 



Silver 1375 



Chlorine 4-5 



or in this compound, an atom of silver is com- 

 bined with an atom of chlorine. 



In all these examples, the atomic weight of 

 chlorine is exactly 4%5. 



4. It has been long known, that when chlo- 



* The chloride of silver, while on the filter, must be washed with distilled 

 water. This water should be very slightly acidulated with nitric acid. For 

 want of this precaution, I was long unable to obtain the exact weight of 

 chloride. The reason is, that distilled water often contains ammonia, which 

 dissolves a little chloride. 



F2 



