plaster are fitted together according to the idea of the scholar who is working on the problem. This restored cast is then placed on exhibition close to the original and carefully labelled so that the public can easily see which is which. In this way, with any change in opinion the cast can easily be altered without disturbing the original. Photographs of similar figures or groups are also provided for comparison. In the case of Roman copies of Greek works, casts of other copies of the same work are shown, and there is usually some member of the staff at work trying to reconstruct from these various copies the exact appearance of the original. It is only the exceptional collection in this country, however, which is rich enough in this class of material to be faced by this contingency.
When it comes to mounting sculpture, the question of the height of the base on which it is to be shown is of prime importance. (R. F. Martin, Some Notes on the Relationship Existing between Statue and Pedestal in Classical and Renaissance Times, Museums Journal, vol. IV, p. 333.) No definite rule can be set down, as each piece differs from every other. An excellent device is the use of the so-called "tiering machine," a valuable adjunct to any museum. This machine, developed for commercial purposes, is composed of a plat-
