^{page 105 note 1} Here it should be explained that Dr. Hunt, from having some time back published both in England and France an outline of his principles of Chemical Geology, hasthereby fairly laid himself open to having his views both criticised and disputed; whilst, on the contrary, Dr. Hunt's knowledge of my views on this subject could be only derived from the allusions to my opinions scattered through the two papers relating to this controversy in the Geological Magazine of October 1 and the Chemical News of October 4 of last year. Although his virulent criticism might therefore be considered as hardly fair; still, so far from objecting to it, I feel truly thankful to Dr. Hunt for thus enabling me to strengthen the weak points, and inspiring me with more confidence than before in the resumé of the views on Chemical Geology put forth in a lecture to the Chemical Society, now in the press.

^{page 109 note 1} It must be remembered tbat these gases are supposed to be formed at an instant of general combination in sitû, and not gradually gathered from the realms of space.

^{page 110 note 1} Dr. Hunt does not merely content himself with mere accusations of ignorance, for when disputing my assertion that “reactions of the compounds of magnesia with carbonic acid in an artificially compressed atmosphere of that acid,” had long been employed on a large scale, he uses the words “here it becomes difficult to admit the plea of ignorance, which suggests itself for most of Mr. Forbes's previous errors and mis-statements.” I may merely add that, since the appearance of Dr. Hunt's communication in the Chemical News of January 17, I have received various communications from Chemists and others, connected, or acquainted, with this manufacture, not only offering to supply more facts in corroboration of the truth of my assertion, but also directing my attention to an expired patent, taken out many years ago (No. 9102, a.d. 1841) by the late Mr. Pattison, of Newcastle, in which these identical reactions are embodied.