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210 but when a little pure ammonia was added to it, a very faint precipitate of oxalate of lime was produced.

No. 6. Bottle, little solution of potash; tube, white arsenic in pieces and powder. This bottle was opened because of the appearances, in October 1829, having then remained three years undisturbed. The arsenious acid was to all appearance unchanged. The solution of potash was turbid and foul. On chemical examination, it proved to have acted powerfully on the glass. It had dissolved so much silica as to become a soft solid, by the action of an acid, and it had also dissolved a considerable quantity of lead; but there was no trace of arsenious acid in it; so that this substance, although abundantly volatile at 600°, had not risen in vapour when aqueous vapour and air were present at common temperatures.

No. 7 was some of the sulphuric acid used in these experiments, preserved for comparison.

No. 8. Bottle, solution half sulphuric acid, half water; tube, pieces of muriate of ammonia. When this bottle was opened, the pieces of muriate of ammonia presented no appearance of change; there was no moisture about them, nor any appearances of dissection that I could distinguish. The diluted sulphuric acid being examined by sulphate of silver, gave no evidence of muriatic acid; so that muriate of ammonia appears fixed under these circumstances.

No. 9. Bottle, a little olution of per sulphate of iron; tube, crystals of the ferro-prussiate of potash. Both were unchanged; there was no appearance of prussian blue about either the crystals or solution; neither of the salts had been volatilised.

No. 10. Bottle, a little solution of potash; tube, fragments of calomel. Here the potash had acted upon the glass, as in No. 6; but, with respect to the calomel, the volatility of which was in question, there was not the slightest trace of such an effect. No black oxide nor other substance existed in the potash solution, which could allow the presumption that any calomel had passed.

No. 11. Bottle, solution of potash; tube, fragments of corrosive sublimate. Here the potash had acted on the glass as before; carbonic acid had also gained access by the stopper; so that no caustic Potash was present; but there were distinct appearances of the sublimation of corrosive sublimate, and