Mr Edward Sang, in the above cited article, makes most flattering mention of the works which I have published on the subject of Logarithms, and particularly on the great operations performed in the end of the last century under the direction of Prony. I cannot but thank him, yet without wishing to intervene in any way in the controversy between him and the editor of the scientific periodical “Nature.” But I owe it to him, as well as to the honourable Royal Society of Edinburgh, to give explanations on several points of fact and of doctrine which he regards as deducible from my writings; writings which he has misinterpreted, doubtless from an incomplete knowledge of the French language. In preparing the following note I am aware that I am exposed to a danger of the same kind, and therefore count upon Mr Sang's indulgence, as he may assuredly count upon mine.