Menard and others conjecture that mirrors in the time of Homer were not much used, because he mentions them on no occasion, not even where he describes in so circumstantial a manner the toilet of Juno[144]. In answer to this, however, I have two things to observe. In the first place, it is not to be expected that Homer should have mentioned every article with which he was acquainted; and secondly, we are assured by Callimachus, where he evidently has imitated the passage of Homer before-quoted[145], that neither Juno nor Pallas employed a mirror when they dressed. Mythology therefore did not allow the poet to introduce a mirror upon the toilet of that deity. Polydore Vergilius, Boccace, Menard, and others have all fallen into the error of making Æsculapius the inventor of mirrors, though Cicero[146] seems to say the same thing; but the best commentators have long since observed very justly, that the Roman philosopher alludes not to a mirror but to a probe, the invention of which we may allow to the father of medicine, who was at first only a surgeon. When one reflects upon the use made of metal mirrors, particularly at Rome, to add to magnificence and for other purposes, and how many artists, during many successive centuries, were employed in constructing them, and vied to excel each other in their art, one cannot help conjecturing that this branch of business must at those periods have been carried to a high degree of perfection. It is therefore to be regretted that they have not been particularly described by any writer, and that on this account the art was entirely lost after the invention of glass mirrors, which are much more convenient. No one at that time entertained the least suspicion that circumstances would afterwards occur which would render these metal mirrors again necessary, as has been the case in our days by the invention of the telescope. Our artists then were obliged to make new experiments in order to discover the best mixture for mirrors of metal; and this should be a warning to mankind, never to suffer arts which have been once invented and useful to become again unknown. A circumstantial description of them should at any rate be preserved for the use of posterity, in libraries, the archives of human knowledge.