Collin’s Dictionary defines an epigram as “a short, pungent and often satirical poem, esp. one having a witty or ingenious ending.” This was a verse form the poet came to use quite often and with great effect, mostly about historical figures, but also on other subjects.  The basic pattern he uses is a quatrain or single verse of four lines.  In some cases the subject will be treated in a single quatrain (vide Proportion). Others (Vide Figures in Porcelain) will have 12 of more quatrains devoted to them.  The best can easily be compared to the best of Belloc’s.