{ 820 ) 



of course, imi.st be !si(iiate<l on llic line J// A'. If llie compositioiis 

 of the i)luises were expressed in luol. 7o l^ would fall in (lie origin 

 of the eo-oi'dinate system ; this is however, not the case as tiie coni- 

 })Ositions are expressed in i)ercentages by weight. The curve 5. ?i .s\ s^ s„ 

 situated on tiie side surface \V A(/ A is the saturation line of silver 

 nitrate in water-alcohol mixtures; the solubility of this salt in water 

 (point .v) gradually becomes less on addition of alcohol ; the solubility 

 in absolute alcohol is repi-esented by .v^. 



The saturation line of ammonium nitrate in water-alcohol mixtures 

 is represented by /> />i />,> />3 />4- It will be noticed that the soIul)ility 

 of ammonium nitrate in water is much lessened i)y alcohol. The 

 equilibria in the ternary system water, silver niti-ate and ammonium 

 nitrate are represented by the three saturation lines s-r, rq and qp, 

 situated on the side surface W Ag N ; si- indicates the solutions satu- 

 rated with silver nitrate, qp those saturated with ammonium nitrate 

 and rq those saturated with the double salt. On drawing the line 

 irB this will be seen to intersect the saturation line ?-(^ of the double 

 salt; this is therefore soluble in water without (lecom[»osition. 



In order to study the ecpiilibria in the (piaternary system I operated 

 as follows. Instead of water, I took a water-alcohol mixture con- 

 taining 41,8 7o of alcohol and in this determijied the saturation lines 

 or the silver nitrate, ammonium nitrate and the double salt. As the 

 solutions all contained water and alcohol in constant i)i-oportion they 

 must lie in a plane passing through the side Ac/ A' of the prism 

 and intersecting 1(^/1 in a j)oint a indicating a 41,8 "/o alcohol. In 

 this manner I found the three saturation lines s^)\ , i\q^ and q^p^ 

 which therefore are all situated in the surface a Ag X : if the line 

 al) is drawn it will be noticed that this branch intersects i\q^ 

 showing that the double salt is also soluble without decomposition 

 in dibite alcohol. 



In a similar manner I determined the saturation line in water- 

 alcohol mixtures containing 71,23 and 91,3 "/o of alcohol ; I always 

 found three branches in the ligure: they are represented by ,v.,r, , r//, 

 an<l (j.,p^ and by s,); , )\q, and q,p,. 



As the line bD intersects the saturation line q.^)\, the double salt 

 is soluble without decomposition in 71,23 Vo alcohol ; with the line 

 cD it is dillerent; this no longer intersects the saturation line q^)\ 

 of the double salt but oidy that of the silver nitrate )\.s^ showing 

 (his is decomposed by 91,3 "/„ alcohol with separation of silver nilrate. 



As the solubility of the components iii absolute alcohol amounts 

 to a few percent oidy, I have not investigated the ternary system 

 alcohol — silver nitrate — ammonium nitrate but there is h^-dly 



