We apprehend that few of the readers Of the Scientific American can be fully aware of the difficulties which attend the publication of a journal devoted to scientific and mechanical subjects. We know, from an experience of twelve years, that whoever undertakes an enterprise of this character will find his path no bed of roses. The care, the anxiety, the study, and the information required to render such a journal popular, are known only to those who have had the severe experience. One of the chief difficulties in maintaining such a journal arises from the fact that readers of scientific literature are, among the great mass of the population, very fcw, in comparison with those who read newspapers whichrequire no special effort of the mind to digest their contents. 4nother reason is that the general news of the day interests every individual and family, while the contents of scientific periodicals embrace comparatively only a limited number of popular subjects. That our readers may catch a glimpse of the roughness of the road over which such journals are compelled to moveif they movc at allwe give thc following list (drawn up from memory) of sixteen journals which have " gone under," to use a timely expression : New York State Mechanic, Jfeclwnic's Mirror, Farmer and Mechanic, Scientific Mechanic, American Artisan, Mechanic's Magazine, The Mechanic, American Jiechanic, Engineer's Journal, EureJea, Mirror of the Patent Office, Polytechnic Journal, Pen and Lever, Railroad Advocate, Inventol and JIechanic's JO!!1"nal, American Engineer. If there still exist any journals similar to the above, except the Scientific American, they are only just wearily dragging along, and will probably cease altogether by the 1st of January next. All of the above sixteen journals were commenced in periods of prosperity, and, with few exceptions, they exhibited a fair amount of ability and industry in their management. The Farmer and Mechanic feebly existed through several years and finally expired. The Mechanic's Magazine was backed by the capital of one of the wealthiest publishing houses in New York. The Polytechnic Journal was in the hands of tolerably able men ; and the Americal^ Engineer, wh'ch received its deathblow dnring the recent "panic," exhibited signs of considerable "gumption." All these seeming advantages, however, could not save their lives. Of those literary ephemera which every now-and-then flutter feebly over the fairy fields of science and art, then fall into the gulf of oblivion, it may be said " They come like shadows, so depart. Almost every journal of this class which has appeared within the last, eight or ten years, as been born with a terrible grudge against the Scientific American, and we have been regularly "barked at" once or twice a year by somenew rival. Some of these puny periodicals have existed for one year, SOme for six months, and some have made only one bow to the public and then expired ; and if it had been unavoidably necessary for them to pay us for the official lists of Patent Claims so often surreptitiously copied from our columns without credit, several of those journals would have died in a much shorter time. We wish it to be understood that in alluding to thc failures of the publications named in this article we do not mention the fact for the purpose of e4ulting over their early death, or of conveying the idea that any remarkable shrewdness in the management of the Scientific American has kept it alive aud made it so popular among mechanics and inventors throughout the world ; but in recording our observations of the catastrophes of old contemporaries, our object is to caution any lili-putian litcmry gladiator who may cotem-plate rushing headlong into this dangerous arena. One-idea men can never succeed in the business of scientific journalism, as many have already learned by bitter experience. So far as the Scientific American is concerned, we will not say that the " hard times" have not probably affected its circulation, but we can say that, in spite of the pecuniary panic that has recently convulsed the commercial world, our journal has nearly as many subscribers as at thc close of the last volume, at which time the list is always largest.