FOOTNOTES:
[38] The separately written oe, ae are ‘digraphs’, because the sounds they represent are in modern pronunciation not diphthongs, though they were such in classical Latin; but ch, ph, sh are also digraphs. Æ, æ, Œ, œ, are rather single letters than digraphs, though they might be called ligatured digraphs.—H. B.
[39] To justify the use in ordinary printing of these symbols (as against the use of 4o, 8o, 12o, a prevailing French fashion which is preferred by some writers), it may suffice to say that the ablative cases of the ordinal numbers quartus, octavus, duodecimus, namely quarto, octavo, duodecimo, are according to popular usage represented by the forms or symbols 4to, 8vo, 12mo; just as by the same usage we print 1st and 2nd as forms or symbols of the English words first and second.—H. H.
[40] See [page 49] for an exception to this rule.
[41] The selection is arbitrary; but the examples are given on the authority of the Oxford University and Cambridge University Calendars, the Post Office Guide, Bartholomew’s Gazetteer, Bradshaw’s Railway Guide, Crockford’s Clerical Directory, Keith Johnston’s Gazetteer, and Stubbs’s Hotel Guide.