This is from your note on Cramsie’s book:
p. 43 “Some historians have linked the invention of the Roman serif to the carver’s chisel…. Another more recent theory has linked it to the invention of a square-cut writing implement; not a reed or quill, but a flat brush….”
[Father E.M. Catich should be identified as the author of the second theory which is now the preferred one.]
In saying this, like many others you do some injustice to W. R. Lethaby, who in his: ‘Editor’s preface’ to Edward Johnston, Writing and illuminating and lettering (London, John Hogg, 1906), pp. x-xi, has this:
“The Roman characters which are our letters today, although their earlier forms have only come down to us cut in stone, must have been formed by incessant practice with a flat, stiff brush, or some such tool. This disposition of the thicks and thins, and the exact shape of the curves, must have been settled by an instrument used rapidly; I suppose, indeed, that most of the great monumental inscriptions were designed in situ by a master writer, and only cut in by the mason, the cutting being merely a ﬁxing, as it were, of the writing, and the cut inscriptions must always have been intended to be completed by painting.”
Lethaby was certainly the true ‘author’ of the theory.