In this one part virgin wax is dissolved in two parts turpentine with a few drops of boiled linseed oil. The pigments are ground in boiled linseed oil with the addition of this medium. The plaster ground, well dried, is soaked with hot boiled linseed oil diluted with an equal quantity of turpentine. It is then grounded with several coats of oil paint for a priming and smoothed with pumice stone. The painting can be executed in a thin water colour technique or with a full body, and dries lighter than when wet and with a dead surface.

§ 42. Encaustic Painting in general in Ancient and Modern Times. — (See Cros and Henry, L' Encaustigue et les autres precedes de la peinture chcz les ancicns, Paris, 1884; Flinders- Petrie, Hawara, &c., London, 1889; O. Donner v. Richter, Vbcr Technisches in der Malerei der Altcn, Mtmich, 1885; Berger, Beitrdge zur Entwickelungs-Geschichte der Maltechnik, ii. 185 seq.; Munich,

1904)-

Although in modern mural painting wax is employed to secure a matt surface, in ancient times it appears to have been valued rather from the depth and intensity it lent to colours when it was polished. It there represented an attempt to secure the same force and pictorial quahty which in modern times are gained by the use of the oil medium. We are told of it by the ancients that it was a slow and troublesome process, and the name of it, meaning " burning in, " shows that the inconvenience of a heating apparatus was inseparable from it; yet it seems at the same time to have been a generally accepted technique, and Greek writers from Anacreon to Procopius treat " wax " as the standard material for the painter. Nay more, hardly a day now passes without every one of us bearing testimony in the words he uses to the importance of the technique in antiquity. The Etymologicum magnum of the 12th century makes the process stand for painting generally {iyKtK.avntvri-t^u)ypa(jyrjHivr{), and the name " en caustic " came to be applied not only to painting but also to sumptuous calligraphy. Then it was applied to writing in general, and the name still survives in the Italian inchiostro and our own familiar " ink " (Eastlake, Materials, i. 151).

The technique of ancient en caustic has given rise to much discussion which till recently was carried on chiefly on a literary basis. Fresh material has been contributed by the discovery, in the eighties of the igth century, in Egypt of a series of portraits on mummy cases, executed for the most part in a wax process, and dating probably from the first two or three centuries a.d. Previous to this discovery there was little material of a monumental kind, though what appears to be the painting apparatus of a Gallo-Roman artist in en caustic was found in 1847 at St Medard-des-Pres in La Vendee, and has been often figured. It should be stated at the outset that the modern process of dissolving wax in turpentine or an essential oil like oil of spike was not known to the ancients, who however knew how to mix resinous substances with it, as in the case of ship-painting (Pliny xi. 16; Dioscorides i. 98). They also saponified wax by boiling it with potash so as to form what was called " Punic wax " (Pliny xxi. 84 seq.), and this emulsion may be reduced with water, and at the same time combines with oil and with size, gum, egg and other temperas. Wax, Pliny says, may be coloured and used for painting — ad cdendas similitudines {loc. cil.); but as the name " en caustic " implies, and as we gather from another of Pliny's phrases, ceris pingcre ac picturam inurere (xxxv. 122), heat was an essential part of the process. Hence the material must have been employed as a rule in a more or less solid form and liquefied each time for use, and not in the form of a diluted solution or emulsion which could be made serviceable cold. It is true that Punic wax mixed with a little oil is prescribed by Vitruvius (vii. 9, 3) as a solution for covering and locking up from the air a coat of the changeable pigment vermilion laid on a wall (see § 35), but the solution is used hot and driven in by application of a heating apparatus.

The accounts of the technique furnished to us by Pliny can be brought into connexion with the actual remains, and Berger and others have succeeded fairly well in imitating these by processes evolved from the ancient notices. It is unfortunate that the most important passage of Pliny (xxxv. 149) appears corrupt. It runs in the received text as follows: Encauslo pingendi duo fuere antiquitus genera, cera et in chore cestro, id est

vericulo, donee classes pingi coepere. Hoc tertium accessit resolutes igni ceris penicillo utendi, quae pictura navibus nee sole nee sale ventisve corrumpitur. Here three kinds of en caustic painting are mentioned, two old and one new (the comparative chronology of the processes need not come into question), and in the two last cases the distinction is that between two instruments of painting, the cestruin and the penicillus or brush. It is natural to suggest that instead of the word cera, which, as wax is the material common to all en caustic processes, need not have been introduced and on manuscript authority may be suspected, some word for a third instrument of painting should be restored. Berger, with some philological likelihood,

conjectures the word caulerio,

which means properly a " branding iron, " but which he believes to be

a sort of hollowed spatula or spoon with a large and a small end by

which melted waxes of difTerent

colours might be taken up, laid on

a ground, such as a wooden panel,

and manipulated in a soft state as

pictorial effect required. Instruments of the kind were found in

the Gallo-Roman tomb in La

Vendee. The second kind of

painting with the cestrum or

verictdum was on ivory and

must have been on a minute

scale. The "cestrum" was certainly

a tool of corresponding size, and

some have seen in it a sort of point or graver, such as that with which

the incised outlines were made on

the figured ivory plaques in the

Kertch room at St Petersburg

(see below); others a small lancet shaped spatula Like the tools that

sculptors employ for working on

plaster. The brush, with which

melted waxes could be laid on in

washes, as was the case on ships,

needs no explanation.

An examination of the portraits

from the mummy cases (see fig. 35)

makes it quite clear that the brush was used with coloured melted

waxes to paint in, in sketchy fashion, the draperies and possibly to

under paint the flesh and hair,

while the flesh was executed in a

more pastos style, with waxes in

a soft condition laid on and

manipulated with some spatula like

instrument, which we may if (From a photograph by W. A. Mansell

we like caU " cauterium " or ^, ,*'^ r.

"cestrum." The marks of such F'?l35.-Mummy of Artemia tool are on several of the heads

unmistakably in evidence, and may

be seen in specimens in the London

National Gallery. There is a

difference of opinion however as to the constitution of the wax. Donner von Richter holds that the wax was "Punic, " i.e. a kind of emulsion, and was blended with oil and resinous balsams so as to be transformed into a soft paste which could be manipulated cold with the spatula. Heat for " burning in " {picturam inurere) he thinks was afterwards applied, with the effect of slightly fusing and blending the coloured waxes that had been in this way worked into a picture. Berger, on the other hand, believes that the coloured wax pastes were manipulated hot with the " cauterium, " which would be maintained in a heated condition, and that there was no subsequent process of " burning in." Flinders Petrie is of opinion that, even in the

dorus with painted portrait,

inscribed " O Artemidorus,

Farewell." About A.D. 200

(Brit. Mus.).