Greek moulds, either for statuettes or reliefs, are somewhat rare; but the British Museum contains a fair number from Tarentum of all kinds (see Plate V.).[406] Those that we possess are mostly for small objects, such as figures of animals; but in the Museum collection there are several moulds for reliefs, as well as for vases of the later class with reliefs (see Chapters XI., XXII.), such as the Calenian phialae with embossed designs.[407] Moulds employed for making stamps of various kinds are also in existence; at Naukratis Mr. Petrie found several circular “cake-stamps” with various designs. Of the moulds used by forgers or others for copying coins we have already spoken (p. 106).[408] The shrinkage of the clay as it dried afterwards permitted the figure to be withdrawn easily from the mould, and it was then ready for the necessary retouching. It is obvious from a glance at any collection of terracottas that there is a great similarity between the various representatives of any one type, and that actual or virtual repetitions are by no means uncommon. This was, of course, due to the fact that only a limited number of moulds were used, corresponding to the different types. At the same time there are in almost all cases minute differences which redeem them from a charge of monotony, and these were obtained in various ways: by varying the pose of the head or attaching the arms in different positions; by retouching before the baking; or by the addition of attributes and colouring. As it has been neatly put by M. Pottier,[409] “All the Tanagra figures are sisters, but few of them are twins.” But retouching is not invariable, and is, in fact, confined to the finer specimens, such as those of Tanagra. In the statuettes from the Cyrenaica and Southern Italy it is the exception. The difference which it effected may be well observed by comparing two statuettes of Eros in the British Museum from Myrina (C 535–36), which are from the same mould. They are identical in style and type, yet one is far superior to the other in artistic merit, just because of the greater finish of detail. The process of baking required great care and attention; for if no allowance was made for the evaporation of moisture, or if too great a degree of temperature was reached, the result was bound to be disastrous. It does not appear that a very high temperature was reached, especially as compared with the pottery. The clay was further insured against too rapid drying by preliminary exposure to the air. A story told by Plutarch[410] of the fate which befell the chariot cast for the temple of Jupiter on the Capitol illustrates the possibility of disasters either from accident or carelessness. The clay swelled up to such a size and hardness that it could only be extracted by pulling the kiln to pieces.