A HISTORY OF NORTHAMPTONSHIRE 



It has however been suggested that the dark colour is not due merely, 

 as Mr. Artis supposed, to a ' colouring exhalation ' permeating the 



articles, but to a distinct chemical 

 action set up by the carbonaceous 

 vapour of which the smothered kiln 

 would be full. The point is one rather 

 for a chemist or a potter than an archae- 

 ologist, and I may be permitted to leave 

 it unsettled.^ 



Arrangements for glazing were also 

 met with (fig. 31) : — 



In the course of my excavations, I 

 discovered a curiously-constructed furnace, 

 Fic. 31. Glazing Furnace. of which I have never before or since 



met with an example. Over it had been 

 placed two circular earthen fire vessels (or cauldrons) ; that next above the furnace 

 was a third less than the other, which would hold about eight gallons. The fire 

 passed partly under both of them, the smoke escaping by a smoothly-plastered flue, 

 from seven to eight inches wide. The vessels were suspended by the rims fitting into 

 a circular groove or rabbet, formed for the purpose. The composition of the vessels 

 was that of a clay tempered with penny-earth. They contained some perfect vessels 

 and many fragments. It is probable they had covers, and I am inclined to think 

 were used for glazing peculiar kinds of the immense quantities of ornamented ware 

 made in this district. Its contiguity to one of the workshops in which the glaze 

 (oxide of iron) and some other pigments were found, confirms this opinion. 



Mr. Artis calls the glaze an oxide of iron. The British Museum 

 and the Jermyn Street Museum of Geology possess cakes of vitreous 

 matter found by Mr. Artis at Castor which was probably used as a 

 glaze, and which consists principally of silicates of soda and lime.' 



Finally, with respect to the ' barbotine ' ornamentation in slip : — 



The vessel, after being thrown upon the wheel, would be allowed to become 

 somewhat firm, but only suflBciently for the purpose of the lathe. In the indented 

 ware the indenting would have to be performed with the vessel in as pliable a state 

 as it could be taken from the lathe. A thick slip of the same body would then be 

 procured, and the ornamenter would then proceed by dipping the thumb or a round 

 mounted instrument into the slip. The vessels, on which are displayed a variety of 

 hunting subjects, representations of fishes, scrolls and human figures were all glazed 

 after the figures were laid on ; where however the decorations are white the vessels 

 were glazed before the ornaments were added. Ornamenting with figures of animals 

 was effected by means of sharp and blunt skewer instruments, and a slip of suitable 

 consistency. These instruments seem to have been of two kinds : one thick enough 

 to carry sufficient slip for the nose, neck, body and front thigh ; the other of a more 

 delicate kind, for a thinner slip for the tongue, lower jaws, eye, fore and hind legs and 

 tail. There seems to have been no retouching after the slip trailed from the instru- 

 ment. 



Such are the chief features of the typical Castor ware as we know 

 it from specimens found in and near the Castor kilns, and such appear 

 to be the general methods of its manufacture. It is not however con- 



' Buckman and Newmarch, Remains of Roman Art in Cirencester, pp. 77-8. 



• An analysis made by Sir Hy. de la Beche, late keeper of the Jermyn Street Museum of Practical 

 Geology, gives : Silica, 69-4.0 ; soda, I4'63 ; lime, 7'8l ; alumina, 2"62 ; with traces of protoxide of 

 iron, protoxide of manganese, magnesia, potash and carbonic acid. 



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