Whewell comments on the chemical notation which 'you send me' and which is about to be adopted by 'the Chemists of the Royal Institution'. He discusses its advantages and disadvantages. Whewell regrets having suggested [in the Journal of the Royal Institution, 1, May 1831, 438-453] the use of accents to represent different oxidation states and urges simplicity and consistency throughout. [This probably concerns the notation outlined by Brande in the Philosophical Magazine, 3rd series, 1, 1833, 304-311]. The letter is watermarked 1831.