a New Class of Salts. 211 



very soluble in water, dissolving in 2| times its weight of water* 

 at 60°. It is still more soluble in hot water, but appears to 

 have a point of less solubility at a particular temperature, for 

 it may easily be crystallized by keeping its hot solution on the 

 sand-bath, while it may not do so on cooling. 



It is decomposed by mixing it with excess of alkali, and 

 suffers the singular transformations with sulphurets of the 

 alkaline metals which have been already alluded to. It un- 

 dergoes no change in weight when heated to 212°, and there- 

 fore does not lose water in the water-bath. 



The following analyses were made by heating the salt with 

 sulphuric acid, and estimating the iron as peroxide, the sodium 

 as sulphate of soda: — 



Analyses I. and II. were made upon a salt obtained by 

 acting on nitroprusside of iron with caustic soda. III. and 

 IV. from a salt prepared from nitroprusside of copper. V. 

 VI. and VII. from the process last described, by acting on 

 yellow prusside of potassium with nitric acid and neutralizing 

 with carbonate of soda; and analyses VIII. and IX. from 

 another preparation in the same way. 



I. 11 '80 grs. gave 3-30 grs. peroxide of iron and 5*87 

 grs. sulphate of soda. 

 II. 10-30 grs. gave 2*93 Fe^O^ and 5-00 NaO, SO^ 



III. 13-767 grs. gave 3-813 Fe^O^ and 6*44 NaO, SO^. 



IV. 21-536 grs. gave 5-932 Fe^O^ and 10-41 NaO, SO^ 

 V. 19-610 grs. gave 5-47 Fe^O^ and 9*89 NaO, SO^. 



VI. 13-545 grs. gave 3-74 Fe^O^ and 6-45 NaO, SO^. 

 VII. 15-740 grs. gave 4*42 peroxide of iron. 

 VIII. 13-788 grs. gave 3-88 Fe^O^ and 6*71 NaO, SO^. 

 L IX. 25-155 grs. gave 7*028 Fe^O^ and 12-12 NaO, ISO^. 

 The combustions were made with chromate of lead. 



I. 9*188 grs. gave 6*870 grs. carbonic acid and 1*30 gr. 



water. 

 II. 8-580 grs. gave 6*315 CO^ and 1*224 HO. 



III. 13*815 grs. gave 10*08 CO^ and I-78 HO. 



IV. 8-765 grs. gave 6-57 CO^ and 1-28 HO. 

 V. 12-010 grs. gave 8-79 CO^ and 1*45 HO. 



VI. 15*070 grs. gave 10*79 CO^ and 1-82 HO. 



VII. 9-000 grs. gave 6*58 CO^ and 1*11 HO. 



VIII. 8*645 grs. gave 6*34 CO^ and 1-184 HO. 



IX. 10-921 grs. gave 8-035 CO^ and 1*309 HO. 



^ * 50*12 grs, saturated solution at 60° gave 14*46 salt; in another expe- 

 riment 42-88 grs. solution gave 12-45 grs. salt, both being dried in the wa- 

 ter-bath. 



P2 



