Of ovens made at Barnstaple there is much the same kind of evidence. In 1851, Thomas Brannam exhibited an oven at the Crystal Palace, where it was described as "generally used in Devonshire for baking bread and meat."[46] In 1786, "Barnstaple ovens" were advertised for sale in Bristol at M. Ewers' "Staffordshire, Broseley, and Glass Warehouse."[47] Thirty-six years earlier, in 1750, Dr. Pococke, who indefatigably entered every sort of observation in his journal, noted that in Devonshire and Cornwall "they make great use here of Cloume ovens,[48] which are of earthen ware of several sizes, like an oven, and being heated they stop 'em up and cover 'em over with embers to keep in the heat."[49] Pococke visited Calstock, "where they have a manufacture of coarse earthenware, and particularly of earthenware ovens."[50] We have encountered only one other instance of ovens having been made at any place other than the North Devon communities around the Fremington clay beds. Calstock lies some 35 miles below Bideford in the southeast corner of Cornwall, just over the Devonshire boundary. As for evidence concerning the manner in which these ovens were used in England, we have already seen that they were built into houses. Jewitt wrote that they "are simply enclosed in raised brickwork, leaving the mouth open to the front." They were heated until red hot by sticks or logs, which were then raked out with long iron tongs.[51] A bundle of gorse, or wood, according to Jewitt,[52] was sufficient to "thoroughly bake three pecks of dough." Pococke's remarks to the effect that the ovens were covered over with embers to keep in the heat suggests that they were sometimes freestanding. However, this could also have been the practice when ovens were built into fireplaces. From an esthetic point of view, the crowning achievement of the North Devon potters was their sgraffito ware, examples of which in Brannam's window display have already been noted. Further evidence in the form of 17th-century sherds was found by Charbonnier around the site of the North Walk pottery in Barnstaple. These consisted of "plates and dishes of various size and section.... Extensive as the demand for these dishes must have been, judging from the heap of fragments, not a single piece has to my knowledge been found above ground."[53] The apparently complete disappearance of the sgraffito table wares suggests that they ceased to be made about 1700. They were apparently forced from the market by the refinement of taste that developed in the 18th century and by the delftware of Bristol and London and Liverpool that was so much more in keeping with that taste.