It is quite clear to a careful observer that the technique of the Albani picture differs from that of the triptych in the National Gallery, for example; but the difficulty is then only stated. It is an extremely puzzling question to determine from an old master painting whether it was painted in tempera or not. Even Ruskin once admitted that he had for a long time been holding up for admiration as the finest oil-painting what he finally discovered to be tempera. The repeated oiling and varnishing to which Italian pictures have been submitted renders the task of discriminating the original medium one of the greatest perplexity. When to this is added the further statement that in some pictures it would appear that the under-painting which gives the shadows is in tempera and the glazes in oil colour, the danger of making such dogmatic statements as those already mentioned, is still more apparent. The information which we possess as to tempera painting in the fourteenth century is derived from the "Trattato" of Cennino Cennini, and this has just been re-translated by the one person in England, who, more than anyone else has practised and understands tempera work. Mrs. Herringham, who has for years worked in tempera and copied the Quatrocento pictures in the National Gallery, has discussed this abstruse question, and to her knowledge, derived both from personal conversation and from her invaluable book,[I] I have obtained much information, and have coupled it with close personal examination of the pictures, and some interesting experiments. I think, in considering tempera painting, one factor, that of climate, has not always received sufficient attention. Mr. Spencer Stanhope has expressed to Mrs. Herringham that tempera never dries completely in this country, and should not be varnished, but that has not been her experience. It, however, expresses in crude statement, the difficulty there is in this moist climate in using tempera satisfactorily, and there is little doubt that part of the success of Italian tempera work is due to the climate in which the artists worked. It is quite clear from Mrs. Herringham's work, that tempera painting, by which I mean strictly yolk-of-egg painting, is capable of the soft transparent effects which are to be seen in Perugino's pictures, and that no admixture of another vehicle with the egg is needful. It is not, however, clear whether the _whole_ of many of his pictures were painted with yolk of egg alone.