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1830.] 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 chloride 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 sublimation 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 examining 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;