Filarete’s Trattato dell’ Architettura, dating about 1464, is not the source of the usage, and as far as can be seen at present the credit, if it be such, of the invention of the term ‘Gothic’ rests with Vasari.
EGG-SHELL MOSAIC.
[See § 33, Pictorial Mosaics for Walls, etc., ante, p. [93].]
This reference on the part of Vasari to ‘musaico di gusci d’ uovo,’ ‘mosaic of egg-shells,’ is puzzling. In his Life of Gaddo Gaddi (Opere, I, 348) he is more explicit, and states there ‘Dopo ciò, ritornò Gaddo a Firenze, con animo di riposarsi: perchè, datosi a fare piccole tavolette di musaico, ne condusse alcune di guscia d’ uova con diligenza e pacienza incredibile; come si può, fra le altre, vedere in alcune che ancor oggi sono nel tempio di San Giovanni di Firenze.’
The Lemonnier editors of Vasari added a note to this passage to the effect that one of these small plaques, representing a Christ with an open book in His left hand, was preserved when they wrote in the Uffizi, and that the mosaic was ‘composed of very minute pieces of egg-shell united together with a diligence and a patience truly incredible.’ This piece is now in the Chapel in the Bargello and Dr Giovanni Poggi has had the kindness to examine it minutely. He reports that there is no sign of the use of egg-shell in it, but that it is a finely executed mosaic of small pieces of coloured materials of a hard substance, in all respects similar to the portable Byzantine mosaics of which there are two notable specimens in the Opera del Duomo at Florence (Gori, Thes. Vet. Diptychorum, III, 320 f.). Eugène Müntz noticed various examples of this kind of work in an article in the Bulletin Monumental, 1886, and one of them, an ‘Annunciation’ in the Victoria and Albert Museum, is a typical piece. It is composed of tesserae of minute size of different coloured marbles, lapis lazuli, etc., on a ground of gold formed of little cubes of the metal, all bedded in wax or similar yielding substance. There is no sign of the use of egg-shell, and indeed the idea of a mosaic of pieces of egg-shell seems absurd, because there is no variety of colour, and therefore no possibility of mosaic effect without painting each piece some special hue.
Were it only Vasari who mentioned this supposed egg-shell mosaic the matter might be passed over, but as a fact one of the chapters of Cennino Cennini’s Trattato is devoted to this very subject. He there describes, c. 172, what he calls a ‘mosaic’ of small cubes of the pith of feathers and of egg-shells, but the technique as he explains it is not mosaic, properly so-called, but rather an imitation of mosaic by means of painting on a roughened ground giving something of the effect of a ground laid with tesserae. Egg-shells are apparently crushed down on the surface so as to give it a sort of crackled appearance, and varieties of colour are added by the paint brush. Vasari mentions in his life of Agnolo Gaddi, Opere, I, 643 f., that he had seen a MS. of Cennino’s treatise, and it is possible that he remembered the heading ‘musaico di gusci d’ uovo’ and, with his instinct for giving a personal interest to everything, attributed to one of his early Florentines, Gaddo Gaddi, the use of the supposed technique. We have not been able to hear of any extant piece of work corresponding to Cennino’s description, though we have to thank several expert authorities for kindly interesting themselves in the matter. Cennino’s notice is appended in the original. It does not occur in the Tambroni text.
Description of the technique in Cennino Cennini, Il Libro dell’ Arte, ed. Milanesi, Firenze, 1859, cap. clxxii.
‘Come si Lavora in Opera Musaica per adornamento di Reliquie; e del Musaico di Bucciuoli di penne, e di Gusci d’ Uovo.
... A questa opra medesima, e molto fine, buccioli di penne tagliati molto minuti sì come panico e tinti sì come detto ho. Ancora puoi lavorare del detto musaico in questo modo. Togli le tue guscia d’ uovo ben peste pur bianche, e in sulla figura disegnata campeggia, riempi e lavora sì come fussi coloriti: e poi quando hai campeggiata la tua figura coi colori propii da cassetta, e temperati con un poco di chiara d’ uovo, va’ colorendo la figura di parte in parte, sì come facessi in su lo ’ngessato propio, pur d’ acquerelle di colori; e poi quando è secco, vernica sì come vernici l’altre cose in tavola. Per campeggiare le dette figure, sì come fai in muro, a te conviene pigliare questo partito, di toglier fogliette dorate, o arientate, o oro grosso battuto o ariento grosso battuto: taglialo minutissimo, e colle dette mollette va’ campeggiando a modo che campeggi i tuoi gusci pesti, dove il campo richiede oro. Ancora, campeggiare di gusci bianchi il campo; bagnare di chiara d’ uovo battuta, di quella che metti il tuo oro in sul vetro; bagna della medesima; metti il tuo oro come trae il campo; lascia asciugare, e brunisci con bambagia. E questo basti alla detta opera musaica, o vuoi greca.’