The Iowa Farmer, published at Des Moines, Iowa, speaking of the SCIENTIFIC AMERICAN, says :— " This is one of the most valuable publications in the country. To the mechanic and inventor it is invaluable. In it may be found a notice or description, and frequently an engraved illustration, of the most important and useful discoveries of the day in all the arts, both in Europe and the United States. It is highly and deservedly prized by every intelligent workman in the mechanic arts, and receives from them a generous support. It is as necessary and useful to them as any of the tools of their trade, for in its beautifully printed pages they find a record of the result of the toils of years of the greatest minds of the world. A friend who stopped a few days in Chicago on his way West informed us that at a lecture which he attended there one evening, a large portion of the audience were mechanics, and he thinks he saw not less than fifty of them with this paper in their hands reading it, which they no doubt had just received from the Post Office. It gave him an exalted opinion of the intelligence of the workmen of Chicago."