Thanks WW for his Mechanics ['An Elementary Treatise on Mechanics', 1819]: WW has made too many 'concessions to the cramming system...and that the work would have been productive of more extensive good...had you conformed a little more to the taste of the age and a little less to that of the University'. JH has recommended WW's application to become a fellow of the Royal Society to Joseph Banks. 'Peacock's pamphlet is singularly stupid' and not worth being made the subject of a paper war. The new rules of the [Cambridge Philosophical] Society 'are very good with I think one exception, that which seems to authorize a system of debating on motions. If this be permitted I cannot concieve the possibility of the Society holding together long or maintaining its respectability'. JH thinks the meetings might receive great additional interest by admitting 2 sorts of communications to be read, one in the form of memoirs, formally got up with a view to publication, and another of a less formal character, containing notices of new facts, sketches of new views, such as give a kind of half publicity by being thus read in public, and thus at once send to secure a claim in case of future discovery, and to excite an interest in the pursuit of truths by railing a kind of philosophical hue and cry'. JH is to read his paper on polarisation to the Royal Society on thursday: 'The object of the paper is to upset certain overhasty generalisations, a nuisance too common in optical science, and to prove the competency of Biot's theory of periodicity to explain all the phenomena of the polarise drings, which in chrystals with 2 axes have hitherto presented anomalies of the most perplexing kind'.