I have spoken with more confidence on the subjects of most of the antique colours than I should otherwise have done, from having a clear recollection of a conversation I had with Sir Humphrey Davy, just after he had been engaged in examining several jars of antique pigments that had been discovered on an estate belonging to the Archbishop of Tarentum[260]. He told me that not one of those he had examined differed in substance from those now used for the same purposes. It will be very difficult indeed to point out with tolerable probability the vehicles used for painting by the ancient painters; certainty, excepting to a very limited extent, is impossible. Time, which has in some instances spared colours so as to permit a satisfactory examination into their nature, has uniformly dried up the substances of the vehicles with which they were laid on; so that it is only where such things are actually named by ancient authors, and that is very sparingly, that we can feel any confidence as to the matter[261]. There is, however, a source of probable conjecture which ought not to be neglected. The use of oils, resins and gums in medicine has been recorded; and the mixtures of those incidentally named, are so nearly what we find used among the earliest painters, of whose works we have any technical account, that it is scarcely possible to believe that they were overlooked by the ancients. For the early pictures on walls, whether the ground were of stone or stucco, lime-water was doubtless found to be a sufficient binder. But to adorn the mummy coffins something more than water must have been required. The Egyptians had the advantage of several native gum-bearing trees. The Acacia Nilotica, which produces the Gum Arabic; the Sarcocolla[262], the gum of which Pliny expressly says is used by painters as well as physicians; and the tree or shrub producing the Gum Senegal; the Terebinth, yielding the manna thuris, Gum Ammoniac[263] and Sandarach[264], were likewise all to be found on the borders of Egypt; and some of these, we know from Herodotus, were employed in embalming, and therefore very probably as vehicles for the colours with which they honoured and ornamented the dead. The desire of showing respect to the remains of those we have once loved is a blessed principle of our nature. It is at once the cause and the effect of that tender care of human life which becomes one of the first principles of civilisation. It is respect and duty, bestowed where no selfishness can ever expect a return, and by the very occupation it forces upon us, breaks the first overwhelming violence of grief, when the day of death, of which no preparation ever took away the bitterness, arrives, and allows us time and occasion to exert that moral resolution necessary to a due submission to the will of HIM, who knoweth best when to give and when to take away.