Ingratitude seldom enters into the composition of a true inventor, and nothing in our business career has afforded us more pleasure than the frequent letters addressed to us by those who have, during more than twenty years, employed the Scientific American Patent Agency. We cannot find room for all the pleasant missives that come to us from our extensive list of clients, but we may give a few as samples of the many. Mr. Daniel J. Gale, of Sheboygan, Wis., has recently secured through our Agency Letters Patent for a "Perpetual and Lunar Calendar Clock." In the fullness of his satisfaction he thus writes: "The fact is, I shall never be able to thank you sufficiently for what you have done for me. I sent you a copy of the paper printed here, which favorably notices my improvement and your great Agency. The fees charged me for my patent have been low enough. Already, by one of my own townsmen, I have been offered $4,000 for my interest in the patent. But I must not take up too much of your I time. Please allow me to add that I regularly receive your valuable paper, the SCIENTIFIC AMERICAN, and that you may number me as one of its stanch friends." Mr. Edwin Norton, of Brooklyn, N.Y., in a recent note, says: "Allow me to express my thanks for the promptness and efficiency with which the business of obtaining a patent for my 'Cinder and Dust Arrester' has been conducted through your Agency--and not only in this case but in several previous ones. This is the _fourth_ patent obtained by me through four Agency within nine months. It gives me pleasure to add my testimony to that of many others, with respect to the very satisfactory manner in which your Patent Agency is conducted." Mr. E. J. Marstens says, in reference to his improved "Field Press"--"I find everything correct. You certainly accomplished more than I expected after the first examination by the Primary Examiner. I hope soon to be able to give you another case." Mr. S. P. Williams, an old client, writes as follows: "I received the patent on my 'Trace Lock for Whiffletrees,' and I am truly pleased with the prompt manner in which you have done the business. It is only a few weeks since I made the application, and I expected that it would be as many months before the patent could be granted." * * * * * PROFESSOR FISKE'S LECTURES AT HARVARD. It certainly argues well for the intellectual character of the readers of the New York _World_ that during the prevalent taste for sensational journalism, it has found the publication of a series of philosophical lectures acceptable. We thank our neighbor for thus making these lectures available to the general public. Their ability is unquestionable; and the calmness and candor which Professor Fiske brings to the treatment of the subject is such as to add greatly to the force of his logic.