[20]. See Note on ‘The Porphyry Tazza of the Sala Rotonda of the Vatican,’ at the close of the ‘Introduction’ to Architecture, postea, p. 108.
[21]. See Note at the end of the ‘Introduction’ to Architecture, postea, p. 110 f., on ‘Francesco del Tadda and, the Revival of Sculpture in Porphyry.’
[22]. About 4 ft. 9 in. In a letter of May 1557 in Gaye, Carteggio, II, 419, Vasari mentions the work as nearly finished.
[23]. The palace in question is the well-known Palazzo Vecchio at Florence, which was adapted for the Grand-ducal residence largely by Vasari himself under the Grand Dukes Cosimo and his successor Francesco. The fountain is the one at present in the courtyard of the palace, carrying the beautiful bronze figure of a boy with a dolphin, by Verrocchio. This ‘putto’ was brought in from the famous Medicean Villa at Careggi, the seat of the Platonic Academy, for the purpose of completing the fountain of which Vasari here gives an account. The porphyry work, both in design and execution, is worthy of the beautiful bronze that surmounts it. The basin rests on a well-turned dwarf pillar of porphyry and this on a square base of the same material. The surfaces are true and the arrises sharp, and the whole is carried out in a workmanlike manner, and by no means betrays a ‘prentice hand.’
[24]. See Vasari’s Life of Michelangelo, Opere, ed. Milanesi, VII, 260.
[25]. That is Cosimo ‘Pater Patriae,’ who died at Careggi in 1464. The portrait in question is shown on Plate III. For what is known about this and other works by Francesco del Tadda, see postea, p. 113 f.
[26]. See Note on ‘Porphyry and Porphyry Quarries,’ postea, p. 101.
[27]. This remark is evidently derived by Vasari from Leon Battista Alberti, who writes as follows in De Re Aedificatoria, Lib. II, ‘At nos de porphirite lapide compertum habemus non modo flammis non excoqui, verum et contigua quaeque circumhereant saxa intra fornacem reddere ut ignibus ne quidquam satis exquoquantur.’ The sense of ‘excoqui’ in this passage, and of Vasari’s ‘cuocer,’ is somewhat obscure, but can be interpreted by reference to old writings on stones, in which great importance is given to their comparative power of resistance to fire. See Pliny, Hist. Nat., XXXVI, 22, etc., etc. Theophrastus, Περὶ Λίθων, § 4, has the following: ‘Stones have many special properties ... for some are consumed by fire and others resist it ... and in respect of the action of the fire and the burning they show many differences....’ The ‘excoqui’ of Alberti probably refers to the resistance of porphyry to the fire as compared with the submission to it of stones like limestone, which are ‘burnt out’ or calcined by the heat. Vasari’s ‘non si cuoce’ is not an adequate translation of Alberti’s word ‘excoqui.’ With a blast heat porphyry fuses to a sort of obsidian or slag, but a moderate heat only causes it to lose its fine purple hue and become grey. This is the ‘rawness’ implied in Vasari’s word ‘incrudelisce.’ To us rawness suggests raw meat which is redder in colour than cooked, but the Italians, who are not great meat eaters, would have in their minds the action of fire on cakes and similar comestibles that darken when baked, and an Italian artist would think too of the action of fire on clay, ‘che viene rossa quando ella è cotta’ as he says in chapter XXV of the ‘Introduction’ to Painting. See Frontispiece, where A1, compared with A, shows the effect of fire on the stone.
[28]. The two porphyry columns, that stand one on each side of Ghiberti’s Old Testament gates at the eastern door of the Baptistry of Florence, serve to point a moral about the untrustworthiness of popular sayings. When these apply to monuments it usually happens that the monument itself hopelessly discredits the saying. The porphyry columns in question are perfectly normal in colour and show no recognizable trace of the action of fire. Villani (Chronicle, bk. IV, ch. 31) says of these columns ‘The Pisani sent them to Florence covered with scarlet cloth, and some said that before they sent them they put them in the fire for envy.’ If we rationalize a little we can imagine that the scarlet cloth, the use of which by the Pisans in connection with porphyry shows a most lamentable absence of taste in colour, would at first sight seem to take the colour out of the porphyry and make it look grey through contrast. Hence may have arisen the impression which gave rise to the saying. Boccaccio, in his commentary on the passage in Dante (Inferno, XV, 67), in which the ‘blindness’ of the Florentines is referred to, notices this affair of the columns as one explanation of this accusation against his countrymen.
[29]. On the subject of serpentine some misapprehension exists. Mineralogists apply the term to a soft stone of a green hue with long curling markings through it, which in their form suggest lacertine creatures and account for the name of the stone. It derives its colour from the presence of a large percentage of manganese in union with silica, and contains twelve or so per cent. of water. A penknife scores it easily. The ‘Verde di Prato,’ a dark stone used in bands on Tuscan buildings, of which there is question in a subsequent section, postea, p. 43, is a species of true serpentine.