In the " New York Daily Times " of the 26th ult., Mr. L. L. HiH, of Westkill, Green Co., N. Y., the alleged discoverer of taking daguerreotypes with all the natural colors of flesh and flower, published one of the most unreasonable letters respecting his alledged discovery that has ever appeared before the public. He says, " attempts have been made to supersede me both here and in Europe, and it would appear that there are those among my own countrymen that would betray the honors that grow upon their own mountains, and deliver them into the hands of La Belle France." The meaning of this flowery burst is explained in the following sentence :—" It is well known that shortly after my announcement was made, M. Niepce, of France, made a similar statement, and that, too, because of this same publication abroad." These remarks are unjust and unworthy of an American inventor—if Mr. Hill is one.— None of his countrymen have ever thrown any aspersions upon his character or efforts, and the insinuation about betraying the honors that grow on our mountains, and about Niepce trying to steal his honors are merely groundless assertions. To obtain colored daguerreotypes has always been a desideratum, and long before "Mr. Hill was a daguerrean artist, —we presume so—in 1840 a paper was published in the Philosophical Magazine on this very subject, and Daguerre himself, before that, had sometimes obtained colored pictures painted by the sun. Colored daguerreotypes are not new things, but there has always been a difficulty about obtaining the colors and rendering them permanent. Many artists have for years been in pursuit of making the grand discovery, and it is reasonable to suppose that M. Niepce, who has grown up with the art, had]made experiments long before Mr. Hill, and without any knowledge of his efforts, or that such an artist was living. In the Daguerrean Journal, published in this city, it was stated that Mr. Hill's pictures would be exhibited in New York City, in September 1851; at that time and up to the present, no hint was given by Mr. Hill how his process was conducted, or a word said about the material he used. His pictures were not exhibited, but some months before that, M. Niepce had taken colored daguerreotypes, and had exhibited them ; and in the very first number of Vol. 7, (last volume) Scientific American, we published the process —being the first one in the country that did so—of M. Niepce, for taking these pictures. This process will be found on page 3, said volume. M. Niepce does not appear to be a braggadocio; he made certain experiments in the art, and like a lover of science, simple and childlike, he published, without guile, the whole processes by which he obtained the said results. Instead of becoming prejudiced against this French artist, he rises higher in our estimation by the sinister expressions contained in Mr. Hill's letter. The process of Mr. Hill may be entirely different and produce far more perfect pictures, but he has certainly suffered no one to rob him of any honor, since he has kept his discovery all to himself. This he has a perfect right to do, and it may be for his benefit to act thus, but he should not, as a man and professed Christian, breathe a foul breath upon those who have done him no evil. We will rejoice, and so will all his countrymen rejoice, if he has made the important discovery he professes to have made ; we will be glad when the evidence is adduced, to be able to say,'' an American artist has done thus and so, to benefit art and ennoble his country." In the meantime let us say that the published descriptions of Niepce's process have been made the subjects of experiments here as will be found on page 46, this Vol., Sci. Am. Mr. Hill publishes a great number of certificates (one from Prof. Morse) all written in very flowery language, speaking of the reality of his discovery and the beauty ol his pictures. None of these certificates are satisfactory, from the fact that not one of them makes the statement of knowing anything about the process, or of having seen it gone through with from" beginning to end. The process which Niepce has published to the world is his own discovery, he is the inventor; if Mr. Hill's is different he is entitled to it; all he has discovered that is new and and useful, happy will we be to defend, and speak well of his title and right to the same.