5ll> Mr. VV. W. el. Niccil cm the 



hnvo rniscMl jjrnvo ilonhtH, nn<l inclino inn to l.lin opinion that 



Wlll(M % of rr\ slalli/al ion is in« lis! m.<- u \A\\\ I do, whoil lllO salt, is 



dissolved, from wutnr <»l solution. Tins, howovor, Aokw not 

 llfFeot the aboYe ! It is iininnlorinl for tho nbovo ttr^nmont 



whether the hydrate ts read) formed in tho solution, or the 



■ill is lorccl l>\ conditions of tempo rn tun \ kw to curry with i< 

 that 11 ii in I m m • of w&tcr-inolncnlcH Mio oflrH, on tho mnloonltir 



volume would be the sttme *• 



I ooino now to tho second pari ol Iho subject. 

 Saturation in Solutions oj two Salts, 



Hitherto we have considered sninration in the solution of 

 ;i ingle .ill. What laws govern the saturation of n solution 

 NMih two or more salts? I shall oonflne mjf remarks lor tho 



present to solutions of <mU two Halts; and Ibis implies that 

 ll»o\ are sails containing tho same metal or the same salt 



radioaL 



This is ;i Subject, which presents considerable experimental 

 difficulties, and it has been attacked by but n lew oxpori- 

 mentersj the ohief of whom are :— 



KoCC (IS KM, liiebi^r's Annalai, xxxiv. pp. LM50 271. 

 Kakmin (1841), hiebin\s Annalrn % \l. pp. 11>7 -2(H). 

 I\h una; ( IH(M ), lor. rit. pp. 145 280i 



Iudokik (IS,;;), ToiM-m. Annalm, cxlviii. pp. l. r >(; and 



Others who have touched upon ii are : — 



U.KONAHI.T, Jottnt. tlr /'harm, rt </r <'/uniit\ xliii. p. IS/, 

 _x I i x . p. is;. 



I *i a ii, .1//;/. tlrr ('/i. ii. Vharni. xcix. p. "221. 



Longchamp, Otto •Graham, ii. 2, p. iss. 



HcilAUICKKKLK, Journ, lit' I'lmrm. \\\\ wii. p. 2(>S, 

 ToliMClt (double sulphates), Ann. Cli.u. /'harm. XCV. p. IDS. 

 Ilol'orc eonsidei in;- (lie nvsults oblained l>v former observers, 



I shall describe my own experiments and state their results. 



Kotir sails w.mv taken lor examination the chlorides ot 

 sodium and potassium, and tho corresponding nitrates; and 

 then solubility and dansitv at 20° ( \ worn carefully deter- 

 mined in the following way, A large bath, fitted tip as 



* li [| QurloUl that tho Icinponitimvs uul tU° lHV\should ho 



marked out no detinitol^ mi thoso at which decomposition of hydrated salts 



fekei plSOSt Thus, n nhovo, is tho A"' ai which joodimn onrhoiuito 



and sulphate decompose; Uit(<l u <UI o molts at :::;•■. rim soluhilitv of 



Sr( NO.,), iuoronsos mho Ii I. .mm im p o 1 1 \ alt «m ". ' ' i , i ,-.hIi,- ( |, w IhI<- (Ii«« m'uno 



lath i oa with SrU.. The solubilitij of MuN<> 4 , which drops 



suddenly at 54°, remain* constant from 64° for more than 20°: ivso,, 

 maximum at '•'• I rhe molting point dotorniinationa of Wiedemann 



ri\>- critical points nt ."..' . iuk! \) ' ' ( \\ iod. ./;,.,... \ N u. p, ,><;| ), 



