Charles Mackay, during his late visit to the United States, discovered, amongthemany other wonderful things to be found here, that we possess a catalogue of " institutions " more numerous than he had met with among any other people. This term in former days could only signify some august establishment, either civil, political, or eleemosynary, but now it dignifies many an object of every day concern, and can as well apply to a match factory as to a Cambridge or Oxford university. Now, we modestly claim that the SCIENTIFIC AMERICAN is one of the recognized " institutions " of which the United States is said to be so prolific; why, therefore, should it not have its anniversary—its holiday ? Bt patriots, great and small, prate loudly about independence—let orators talk about our great institutions, and say fine things of our great national bird—we have no word of opposition to say against these and kindred demonstrations. Our object now is simply to announce to th9 busy, thinking, earnest citizens of tlif great republic, from Arostook, Maine, to San Diego, California, that in the diurnal revolution of the earth the SCIENTIFIC AMERICAN is just about to slip out of its thireeenth year, and will enter upon its fourteenth volume on the 11th of September next, which is close upon our heels. The past year has been an eventful one—the financial and the business centres have been convulsed, and a heavy cloud of disappointment fell upon many bright hopes and cherished plans. The shock came upon us at an inopportune moment, just as we were about to enter upon a new volume, when more than six thousand book subscriptions were about to expire ; and although we felt the effect of a diminished subscription list, . yet our old and well-tried friends came forward, and did nobly towards extending the circulation of their favorite paper. To one and all of our readers we tender our sincerest thanks, and we also appeal to them to not only promptly renew their own, but '8lso to gather up additional subscriptions for the new volume. Shall we make this appeal to them in vain ? We believe not; and if all our subscribers will turn out among their neighbors, and induce some of them to subscribe, instead of twenty-five thousand, we shall have a subscription list of at least fifty thousand. We make this appeal the more urgently because, after careful consideration, we have determined not to continue the system of paying prizes, nor to begin the employment of traveling agents. We prefer 10 throw our cause upon those generous friends who have so long sustained the SCIENTIFIC AMERICAN, and we. believe that we shall not be disappointed, after a continued success of thirteen years. We invite especial attention to the prospectus of the new volume, published in another column, and conclude by stating that it will be our endeavor to make the SCIENTIFIC AMERICAN still more useful and interesting than it has hitherto been.