With the requisite railroad facilities supplied, it is certain that the growth of a region so abounding in the most essential reliance of mechanical industry, as Northwestern Massachusetts, cannot be measured by the snail's pace which marks the progress of an agricultural district. The farmer's interests are indeed equally promoted with those of other industrial classes, by the opening of railroads, but these do not increase the number of farms or farmers within our borders, nor stimulate the growth of agricultural towns. It is mainly by her manufactures and commerce that Massachusetts has become so prosperous and wealthy. It is because the commercial and industrial interests of the whole State require it, that another route to the West has become a necessity; and it is because such immense resources yet remain to be developed, and such a gigantic power to be employed, in Northern Massachusetts that the new route must pierce the Hoosac Mountain, if it is possible and practicable. That it is possible to tunnel the Hoosac Mountain cannot be doubted by any sane person who has inspected the half mile already excavated. All of the eminent engineers, whose reports upon the enterprise have been published, say it can be done; nor do any of its opponents pretend to question its practicability. But in order to estimate properly the magnitude of the work, its possible and probable cost, and the time within which it can be done, it is necessary to know what has been accomplished in this department of civil engineering. Fortunately, this needed information is contained in Mr. Charles W. Storrow's very able report on European tunnels. Mr. Storrow is a distinguished civil engineer, who made a journey to Europe in the summer of 1862, by request of the Hoosac Tunnel Commissioners, and with the approval of the Governor and Council, for the purpose of examining the most important tunnels there constructed, and, especially, the one in progress under the Alps. He describes twenty-two tunnels which he visited, besides that of Mt. Cenis. Fourteen of these are in England, seven in France, and one in Switzerland. Two of them are upwards of three miles long, and many of them between one and two miles. Some of the shafts were nearly as deep as the central shaft of the Hoosac. Some of these excavations were made without the aid of shafts, others wholly by means of shafts, without working from the ends at all.