ROMANO-BRITISH NORTHAMPTONSHIRE 



rarer, are painted in artistic fashion — such as two fragments, now in 

 Dr. Walker's collection, on the copper-coloured surfaces of which the 

 potter has gracefully depicted in white and yellow a man's head with a 

 peaked cap, and an arm holding a small axe. But these vessels painted 

 in white, whatever their type, are less frequent and less characteristic 

 than the thumb vases and vessels decorated in self-colour slip which seem 

 to be the most typical Castor wares. ^ 



Mr. Artis has printed some interesting details as to the method by 

 which these wares were baked, coloured, glazed and ornamented in slip, 

 which it will be best to repeat in his own words. As to the baking — 



The kilns (he says) were first carefully loose-packed with the articles to be fired, 

 up to the height of the side walls. The circumference of the bulk was then gradually 

 diminished, and finished in the shape of a dome. As this arrangement progressed, an 

 attendant seems to have followed the packer and thinly covered a layer of pots with 

 coarse hay or grass. He then took some thin clay, the size of his hand, and laid it 

 flat on the grass upon the vessels ; he then placed more grass on the edge of the clay 

 just laid on, and then more clay, and so on until he had completed the circle. By this 

 time the packer would have raised another tier of pots, the plasterer following as before, 

 hanging the grass over the top edge of the last layer of plasters, until he had reached 

 the top, in which a small aperture was left, and the clay nipt round the edge ; another 

 coating would be laid on as before described. Gravel or loam was then thrown up 

 against the side wall where the clay wrappers were commenced, probably to secure the 

 bricks and the clay coating. The kiln was then fired with wood. In consequence of 

 the care taken to place grass between the edges of the wrappers, they could be 

 unpacked in the same size pieces as when laid on in a plastic state, and thus the danger 

 in breaking the coat to obtain the contents of the kiln could be obviated. 



The slate blue or copper colour on the outside of the ' Castor ware ' 

 seems to have been produced generally by a trick in the process of 

 baking, and not by a varnish. 



During an examinatioii of the pigments used by the Roman potters of the place, 

 I was led to the conclusion that the blue and slate-coloured vessels met with here in 

 such abundance, were coloured by suffocating the fire of the kiln, at the time when its 

 contents had acquired a degree of heat sufficient to insure uniformity of colour. I had 

 so firmly made up my mind upon the process of manufacturing and firing this peculiar 

 kind of earthenware, that, for some time previous to the recent discovery, I had 

 denominated the kilns in which it had been fired, smother kilns. . . . The mouth of 

 the furnace and top of the kiln were no doubt stopped ; thus we find every part of the 

 kiln, from the inside wall to the earth on the outside, and every part of the clay 

 wrappers of the dome, penetrated with colouring exhalation. As further proof that 

 the colour of the ware was imparted by firing, I collected the clays of the neighbour- 

 hood, including specimens from the immediate vicinity of the smother kilns. In 

 colour, some of these clays resembled the ware after firing, and some were darker. I 

 submitted them to a process similar to that I have described. The clays, dug near 

 the kilns, whitened in firing, probably from being bituminous. I also put some frag- 

 ments of the blue pottery into the kiln ; they came out precisely of the same colour as 

 the clay fired with them, which had been taken from the site of the kilns. The 

 experiment proved to me that the colour could not be attributed to any metallic oxide, 

 either existing in the clay, or applied externally ; and this conclusion is confirmed by 

 the appearance of the clay wrappers of the dome of the kiln. It should be remarked 

 that this colour is so volatile, that it is expelled by a second firing in an open kiln. 



* It would be interesting, but I have not found it possible, to trace the origin of the shape called 

 above the ' thumb vase ' and of the ' barbotine ' method of ornamentation. Both seem to occur 

 occasionally in Italy and the Mediterranean lands, but neither is common enough to form a definite 

 precedent, such as the red Arretine ware forms for the west-European ' Samian.' 



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