My correspondent has visited the ruined cities of Yucatan; he knows the value of my collections. I have done all in my power to call the attention of American scientists, of the men of leisure and money, to the fact that in New York perfect fac-similes of the palaces and temples of the Mayas could be erected in Central Park, both as ornament to the place, and object of study for the lovers of American archæology who may not have the means, nor the time, nor the desire, to run the risk of submitting to the privations and hardships that those who wish to visit the ruined cities, must inevitably encounter. But alas! all in vain. Three years ago I had casts made from some of the stereotyped moulds made by me of the sculptures at Uxmal and offered them for exhibition in the Metropolitan Museum of Art in Central Park. They have been placed in the cellar, out of the way, "for want of space against the wall." The public has never seen them. I once remonstrated with one of the trustees, and proposed to sell to the museum a copy of the collection of fresco paintings from Chichen Itza, last remnants of ancient American art. The answer of the gentleman was "No! those things are not appreciated, they are looked upon as of no value." Nevertheless, some of the illustrations in this book are photographs of the same despised casts and mural paintings. During the last lecturing season I offered to several literary, scientific and historical societies, to give lectures illustrated with views made by us of the monuments, and enlarged with the stereopticon. In every instance I received the same answer. "Our people are not interested in such a subject." What! Americans not interested in American antiquities! in ancient American history! in ancient American civilization! Desiring to make the subject known before the lecture season was over, _en desespoir de cause_, I asked Dr. John Stoughton Newbury, of the School of Mines at Columbia College, if he could give me a chance to present the subject before the members of the New York Academy of Science. I had no hope of a favorable answer; but to my great surprise Professor Newbury received my offer enthusiastically. Mrs. Le Plongeon lectured on the monuments of Yucatan on the 2nd of March last, at Columbia College. Let the ladies and gentlemen who were present say if the facts and views presented to them were of sufficient interest to command their attention. A lady, Mrs. Francis B. Arnold, residing at 21 West 12th Street, New York, was so pleased that she asked Mrs. Le Plongeon to lecture at her own house to a select party of friends. Let again the ladies and gentlemen who were present at Mrs. Arnold's house, say if there is nothing worth seeing and studying in the remains of ancient American civilization. Let Mrs. Arnold and Dr. Newbury accept our heartfelt-thanks for affording us an opportunity of presenting ancient America to a few appreciative minds, if no more.