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1830.] minute crystals of the substance were even attached to the under part of the stopper in the bottle. Hence corrosive sublimate is volatile at common temperatures.

No. 12 and 13. Bottles, solution of chromate of potash; tubes, in one, chloride of lead in powder, in the other nitrate of lead in crystals. In both these experiments the chromate of potash had acted upon the lead of the glass, and rendered it yellow and dim; so that no indication could be gathered relating to the volatility of the compounds of lead.

No. 14. Bottle, solution of iodide of potassium; tube, chloride of lead. Both remained unaltered; the solution of iodide was perfectly clear and colourless; no trace of the chloride of lead had passed over in vapour.

No. 15. Bottle, solution of muriate of lime; tube, crystals of carbonate of soda. A part of the water has passed to the carbonate of soda; but both it and the remaining solution of muriate of lime are perfectly clear. No portion of either salt has volatilized from one place to another.

No. 16. Bottle, dilute sulphuric acid; tube, nitrate of ammonia in fragments. The nitrate was slightly moist. The acid being examined was found to contain nitric acid, whilst the test acid, No. 7, was perfectly free from it. It would therefore appear that nitrate of ammonia is a salt volatile at common temperatures; although it is just possible that slow decomposition may take place in it, and so nitric acid or its elements pass over.

No. 17. Bottle, solution of per sulphate of copper; tube, crystals of ferro-prussiate of potash. The crystals had attracted most of the water from the cupreous salt; but the solution of ferro-prussiate and that of the copper had their proper colour; neither were rendered brown; no salts had been volatilized.

No. 18. Bottle, solution of acetate of lead; tube, iodide of potassium. The acetate of lead is now dry; the iodide of potassium has taken all the water and formed a brown solution, in which there is free iodine; probably a little acetic acid has passed over and caused the change in the iodide of potassium There is no appearance of iodide of lead in the tube, but there is in the bottle, and most probably in consequence of the vaporization of the free iodine from the solution in the tube.

From these experiments it would appear that there is no