On the Intimate Structure of Crystals. 



287 



specific gravity of from 5*517 to 5*594, and for silver bromide from 

 6'215 to 6'425. Data for calculation are given in the table : 



We are now in a position to compare the diameter of atoms of 

 silver in the free state and in combination. The diameter of chlorine 

 being taken as 2'4954, the. value found in Part I, and that of 

 bromine 2'801, its value in sodium bromide, we obtain from Pro- 

 fessor Miers' formula 



Diameter of Ag in 

 AgCl. AgBr. 



(a) 2-2279 (a) 2-1784 



(6) 2-2399 (6) 2'1307 



The results for (a) and (&) correspond to the different specific 

 gravities (a) and (6) given above, and obtained by different 

 observers. 



The differences between the diameters (a) of silver in combination 

 and that it possesses in the free state are not great. 



On comparing the gross volumes of the haloids given above with 

 their gross volumes in the haloid compounds of the alkalis, it will 

 be observed that the gross volume of bromine in silver and sodium 

 bromides is closely correspondent ; this is because the atomic volumes 

 of sodium and silver have nearly the same relative value. 



Silver iodide, to which we now turn, is one of the most interesting* 

 substances we have yet encountered, and most important results 

 follow from its study. At ordinary temperatures it does not present 



T 2 



