Mr. Phillips asserts that I have been misled by erroneous experiments. My reply is, that the experiment to which he refers, and which I have recapitulated, was carefully made, and is truly and faithfully detailed. In what, then, is it erroneous? It is not incompatible with that which he has produced as a refutation of it, inasmuch as he did not wait the result for which the perusal of my statement should have prepared him, and which he clearly should not have anticipated. He states that chlorine was not evolved from washed manganese at the instant when sulphuric acid was affused upon it. This is not a contradiction of my statement: I affirmed that, after washed manganese had been exposed to the action of sulphuric acid for a very considerable period, I distinctly observed the evolution of chlorine, and that for twelve months afterwards, _under the circumstances detailed_, this continued to be the case:—all this I deliberately re-assert. I have frequently met with specimens of manganese which, upon the first affusion of sulphuric acid, gave off chlorine; but _in general_, as far as my experience goes, _this is not the case_: were it of uniform occurrence, and that the mixture of sulphuric acid and oxide of manganese rendered chlorine evident to the smell, the fact _could not have remained unnoticed till now_. The observations of Mr. Phillips, to which I now refer, did not come into my hands till about three weeks ago. It fortunately happened that I had still preserved the specimen of washed manganese upon which sulphuric acid had been affused, under the circumstances already recapitulated, and it occurred to me that this would afford occasion, as decisive as I could desire, to put the accuracy of my original experiment, and the conclusions drawn from it, to further proof. I am bound to premise that this specimen of manganese, after having been in the first washed and subjected to the action of sulphuric acid, as already mentioned, has ever since remained in [p261] the vessel in which the experiment was at first made, covered with dilute sulphuric acid,—a period of more than eighteen months; and it will scarcely be doubted that, in the course of that long interval, any muriate of lime which it might have originally contained must have been thoroughly decomposed. Upon removing the supernatant acid, the residuary manganese gave sensible evidence of the presence of chlorine; paper stained with the solution of indigo in sulphuric acid was readily bleached by it, &c. I now proceeded to wash the manganese in pure water, and continued to do so until the acid was no longer perceptible to the taste. I then washed it three times successively with distilled water, and after decanting off the fluid of the last washing as closely as possible, added pure sulphuric acid in considerable quantity, and stirred the mixture thoroughly, after it had cooled, with a glass rod. At this time no vapour of chlorine was evident either to the smell or to the usual tests.