The most ancient form of fonts was octagonal, or tub-shaped, built like a tower, as described by St. Paulinus of Nola. Some Norman fonts are round; more often, perhaps, they are of square form, sometimes profusely decorated with grotesque imagery, and supported by a central massive circular stem. If we take away the sketchy chiselling, for which we have suggested a possible reason, no one would consider the St. Martin's font to be of Norman workmanship. Moreover, the sides of the font internally are extremely rough, and it is unlike the Normans to bestow so little in the way of finish.
We may conclude (as I have said) with some confidence that Ethelbert was baptised in St. Martin's Church. No traces have been discovered there of a baptistery—nor, indeed, of any in England before that erected (about 750) by Cuthbert, Archbishop of Canterbury, to the east of the Cathedral. But this does not militate against the theory that he was baptised by affusion, even though not from the present font notwithstanding traditional evidence to this effect in the seals before alluded to.
Reverence and probability alike protest against the idea, entertained by one or two distinguished antiquaries, that the font is nothing but the circular erection once surrounding the top of a well, or puteus, as depicted by Eadwin (1130-1174) in his plan of the herbarium of the cathedral.
Next to the font, we must direct attention to the "West Wall of the Nave." Rugged and uneven as it now appears, there is still method in its building. Its general character is that of roughly-hewn Kentish rag-stones (with occasional blocks of chalk) bonded together by Roman bricks, arranged in sometimes a single, sometimes a double or even triple, course. Here and there a single course of stones lies between the courses of bricks, which are then 9 ins. apart. In other portions of the wall five or six courses of stone intervene between the courses of bricks, so that the courses of stones and bricks do not alternate regularly. The original face of the wall is much obscured by sundry patchings and repairs, and (on the north side) by the erection of a monumental tablet, lately removed to the tower-porch. In the centre, over the present doorway, is an arch or opening, now filled up with courses of Roman bricks and rubble of chalk or flint. The arch reaches to a height of 17 or 18 ft. above the floor level, a few inches of the crown having been cut away, and is on an average 7 ft. 2 in. wide. Whether it reached originally down to the ground, or was merely an opening of the nature of a window, cannot be positively settled, as the fillings-up have not yet been removed. On either side of the arch, at a distance of 2 ft., are two windows (the upper 18 ins. of which, as they now appear, are an extension made in Saxon or Norman times). The original windows (below this extension) have their jambs of chalk-blocks filled in with white mortar, while the arches are turned in Roman bricks and rough voussoirs of Kentish rag-stone, with interstices of bright pink mortar. These windows are certainly built more Romano, and no sufficient evidence has yet been brought forward to upset the opinion strongly held by many archæologists—that they are Roman. The variation of the mortar used in their construction from white mortar in the jambs to pink mortar in the voussoirs of the arch is a very noticeable feature, and can be exactly paralleled in the Roman Pharos at Dover. It is certainly prima facie, a strong evidence of Roman workmanship. The windows are 2 ft. 8 in. wide, and would have measured 4 ft. from sill to crown. Their jambs are splayed at an angle that would allow about 12 ins. for the actual opening on the outer face of the wall. Their sills are respectively 9 ft. 9 in. and 10 ft. above the ground level, and the lower portion of the south window is filled up with thin mediæval tiles, such as we find here and there in the fourteenth-century tower, during the building of which the extended windows were undoubtedly blocked up. These extended windows have no voussoirs, but were cut out of the original walling, and simply plastered. Near them are portions of pink plaster still adhering to the wall.
Excavations have been made below the northern portion of this western wall in hopes of finding some of the original flooring of the church, but could not be further prosecuted because vaults, and even detached skeletons, were met with at a distance of only one foot below the existing pews.
The style of the north and south walls of the nave is much the same as that of the western wall; and behind the wood-work are considerable pieces of pink plaster, remarkable both for its hardness and texture. About this plaster we must say a few words, as it is, in our opinion, an important piece of evidence. It is composed of carbonate of lime imperfectly burned, of silicious sand, and pounded Roman brick, in almost equal proportions. It is true that some examples of this plaster have been occasionally found in Saxon, Norman, and even Early English buildings, but they are feeble imitations, distinguishable by the greater preponderance of sand, neither so bright nor crisp in section, more soft and pliable, and of a dullish colour. Two pieces of plaster were put side by side, one from St. Martin's and another from a Roman villa at Wingham, and to an experienced eye the texture was identical, except that the latter was rather thinner. And on our sending to such an undoubted expert as Mr J. T. Irvine (who had previously expressed much scepticism as to the Roman claims of St. Martin's, though he candidly confessed that he had not seen our recent explorations) a specimen of this plaster, he wrote in reply that, "both as regards texture of tile and lime mixture, and the colour produced thereby in section, it certainly seem to accord with that of good Roman date."