The two portions of the mould were joined while the clay was moist, and pared with a tool, and the orifice for filling was then pierced. Glaze, when used, was applied before the baking, for which only a moderate temperature seems to have been required; this process followed as soon as the clay was dry. In some lamps a small hole or slit may be observed, which some have thought to be for the pin with which the wick was extracted,[[2795]] but it is more probable that it was for a piece of wood which held the top and bottom of the mould together until the clay was united; it was usually covered over before the baking, and may have taken the place of the knobs already spoken of which occur in other forms. The lamps were baked in batches, placed closely together or superimposed,[[2796]] and it sometimes happens that a number are found united together which had coalesced firmly in the furnace, as in Sir Charles Newton’s excavations at Knidos.

Subjects are first found on lamps in the second century B.C., though these are quite of a simple character. Lamps of this date from North Africa[[2797]] have such designs as an altar and fruit, a vase, or a caduceus, a head of an ibis, or a nude incised figure of Tanit; others have merely a wreath round the centre, and these apparently belong to the first century B.C.[[2798]] The number of figures is generally small, it being contrary to the principles of ancient art to crowd a work with minute figures and details. The majority of lamps have only one figure, and few beyond those of exceptional size have more than three. As a rule the treatment is careless and the figures very indistinct, but the lamps with Greek signatures (see Vol. 1. p. [108]) form a notable exception.

It may be imagined that the lamp-maker sought to gratify the taste of his customers by ornamenting his ware with familiar subjects. Purchasers of terracotta lamps were, as has been noted, generally persons of inferior condition, and the subjects on the lamps are in many cases a popularising of well-known myths or even of works of art, such as the Venus types (p. [410]) or the Maenads of the “new-Attic” reliefs (p. [411]). The types of Victory and Fortune are reflections of statues of the period, and are repeated in many bronze statuettes. There are also, as we shall see, occasional references to literature. In Rome the stage exerted little influence, and subjects are rarely taken from the drama (masks are an exception); but the games of the circus and gladiatorial contests found a ready market, and form a large proportion of the designs. The subjects on the lamps, in fact, represent not so much the great masterpieces of art, as do coins or gems, but, like the Greek vases, the popular art of the day, and may be compared with the illustrations of the popular journals and magazines of our own time. On the whole, they are of great value to us as illustrating Roman life and religion, just as subsequently those on the Christian lamps are of inestimable importance for the light they throw on the early ages of our own religion.

As the number of published lamps and catalogues of collections is so very small, the subjects included in the following list are mostly confined to the collections in the British Museum, which are quite sufficiently comprehensive for the purpose.[[2799]] A few additional examples are given from the Guildhall, Vienna, and other collections, from the Antichità di Ercolano, Bartoli’s Lucernae veterum sepulcrales, the Musée Alaoui, and other isolated sources.[[2800]] References to Passeri’s work, Lucernae fictiles Musei Passerii, have been avoided, as it has been shown by Dr. Dressel[[2801]] that nearly all those published by him are false.

We proceed to note the principal subjects in detail, observing practically the same order that was adopted in describing the subjects on Greek vases. They may be roughly divided into eight classes:—

(1) Olympian deities.

(2) Miscellaneous deities.

(3) Heroic legends, etc.

(4) Historical and literary subjects.

(5) Genre subjects.