1830.] On the Limits of Vaporization. 209 



baryta above crystals, but both that and the remaining solution 

 of sulphate of soda is perfectly clear ; there is not the slightest 

 trace of sulphate of baryta in either the one or the other, so 

 that neither muriate of baryta nor sulphate of soda appear to 

 have volatilized with the water. 



No. 2. Bottle, solution of nitrate of silver ; tube, fused chlo- 

 ride of sodium. All the water has passed from the nitrate of 

 silver to the salt ; but there is no trace of chloride of silver 

 either in one or the other. No nitrate of silver has sublimed 

 with the water, nor has any chloride of sodium passed over to 

 the nitrate. 



No. 3. Bottle, solution of muriate of lime ; tube, crystals of 

 oxalic acid. The water here remained with the muriate of lime. 

 In the tube, the oxalic acid when put in had formed a loose 

 aggregation, with numerous vacancies, and with a very irregular 

 upper surface about an inch below the upper edge of the tube. 

 No particular appearances occur in the vacancies ; but at the 

 top there has evidently been a sublimation of the oxalic acid, 

 for upon the crystals and glass new crystals in exceedingly thin 

 plates and reflecting colour have been formed ; these rise no 

 higher in the tube than to the level of the most projecting part 

 of the original portion of oxalic acid ; no appearance of sublima- 

 tion is evident above this, and it seems as if the most elevated 

 parts of the salt have given off vapour, which has sunk and 

 formed crystals on the neighbouring lower surfaces, but that 

 no vapour has risen to the upper part of the tube. On exa- 

 mining the solution by a drop or two of pure ammonia, it was 

 found that a slight precipitate of oxalate of ammonia occurred. 

 The experiment shows, therefore, that oxalic acid is volatile 

 at common temperatures, and had not only formed crystals in 

 the tube, but had passed over to the solution of lime. 



No. 4. Bottle, solution half sulphuric acid, half water ; tube, 

 crystallized common salt. No water has passed to the salt. 

 On opening the bottle, the clear diluted sulphuric acid was 

 examined for muriatic acid, but no trace could be found. 

 Hence chloride of sodium has not been volatilized under these 

 circumstances. 



No. 5. Bottle, solution of muriate of lime ; tube, crystals of 

 oxalate of ammonia. The oxalate of ammonia appeared quite 

 unchanged. The solution of muriate of lime was perfectly clear ; 



p 



