It has become a mighty fashion now to. have public lectures in all our large and small citiesit is quite the rageand a very commendable passion it is if rightly'directed; t this we believe is not always the case. Men of note as fancy speakers and authors are generally the selected lecturers ; they tickle the ear and captivate the heart for the passing hour, but instead of making tp.e hearers " wiser and better," those who believe all they say, are often made more ignorant than they were before. A great amount of trash is also uttered in some public lectures ; there is little that is truly instructive or really true. Now, as " the true is the beautiful," we must say that the universal taste or passion is for the glitter and gaud of the uncertain, in preference to the true. A respectably large audience could not, we believe, be obtained in all this city to hear a course of lectures on Natural Philosophy, while at the same time crowds go to hear mere opinions expressed about Dean Swift and the English Mind, and so on. These things are all very well, but they do not exhibit a strong healthy public pulse, when the weighty matters of science and art, aa was found in the case of Prof. Agassiz' lectures, are neglected. Some of these lecturers also do not exhibit that amount of correct knowledge which we expect of them. On Wednesday evening, the 1st inst., Wendell Phillips, of Boston, delivered one of the course that are called Popular Lectures, in the Tabernacle, this city, and although a very eloquent and humorsome speaker, his information is not altogether to be relied on. The subject was " The Lost Arts," and we must take exception to much of what he said. He asserted that in all that relates to works of the imagination and the fine arts, we,were farbehjnd the people of antiquity. This we do not believe. Shakespare, Milton, and Burns stand above all the ancient poets, and Raphael, Angela, C wva, and Thorwalad..n, al-1 moderns, were at least equal to the ancients in painting, sculpture, and architecture. He said very truly, that" we were apt to think our age the greatest, and that the ancients knew nothing." We are indeed too forgetful of the benefits we have derived from our ancestors, but at the same time there are some who reverence everything that is oldgood and bad, and with an antiquarian taste, deride that which is new and better. There is much ignorance displayed by mere literary men, about the present state of the arts, and Mr. Phillips exhibited not a little. With respect to glass he ,aid :" This beautiful material that administers so much to our delight and comfortdid the ancients know of it 4 Even at the time when some skeptics were disputing upon this ' veiy question, the peasants broke into a house among the ruins of Pompeii which was filM with it. The lie and its refutation came thus together. It was like Dr. Lardner in 1839 writing a pamphlet to prove that a steamship could not cross the Atlantic, while in that same month the Sirius made her voyage to this country. Instead of not knowing of glass, the ancients knew more than we do about it. In the first place, they understood the process of transfusing the color through the glass. Sir George Wilkinson brought from Egypt a small piece of glass, in which there was a figure of a duck, protected by another glass and then covered over again; and all this without destroying its beauty. But I pass to the inquiry, whether they used glass f0r microscopes and telescopes ? If you look at the History of Astronomy, you will find that the Hebrews and Egyptians were acquainted with the shape of the earth. We also read that -the Iliad was put into a nut shell by Alexander. Now this could not have been written in so small a compass without the aid of spectacles. We are also told that Nero had a ring of a peculiar shape and nature, that he looked down into the ring as he sat in the Coliseum, and could see the players distinctly. We are, therefore, led to believe that Nero had an opera-glass." It is a common opinion (inexecusable in an educated man) , that the moderns cannot make as good colored glass as the ancients. This is all nonsense; they can transfuse all colors into the glass, and the manner of covering the duck is quite a common trick among our glass makers. We have seen a miniature on ivory covered with glass and set in a glass frame in Englandthe glass fused all around it, and not a tinge (9f light or shade altered. Could the aneients do that ? This miniature was formerly in the possession of Dr. Beck, ofthis State, who used to exhibit it in his chemical lectures. In glass making, the moderns far excel the ancients. The ancients may have been acquainted with spectacles, but it certainly requires a spectacle vision to discover any evidence of the same. As for telescopes being known by the ancients, Mr. Phillips draws largely upon his guessing powers. The remark about Dr. Lardner is incorrect; he never wrote any such a pamphlet, and never made any such assertions. A man of education, who lectures to instruct the public, should draw his information from good authority instead of troubadour paragraphs which have appeared in some newspapers. Dr. Lardner has denied over his own signature, that he ever said " a steamship could not cross the Atlantic." The common beliefthat the ancientswere acquainted with malleable glass, is founded on as great historical error as that committed by Reese, who says, " a fossil glass is wrought by the Americans and used instead of iron." It is our opinion that there was not a single art known to the ancients which iS not known to the moderns. Some arts, it is true, were lost during the dark ages, but they were all re-discovered, and nothing can be shown as works of ancients which cannot be done now. It is true we have learned much from the giants of old, but then we know all they ever knew, and can do all they could do, and a great deal more. The common opinion about " the lost arts,"that the ancients were acquainted with arts about which we are ignorant, is a legend stamped with about as much truth as the story of " Jack the Giant Killer."