The directors of the Mechanics' Institute, in the Fourth avenue. New York, having met with such success in their endeavors to provide a means of obtaining a good, sound and practical education for the young mechanics of this city, have now determined to extend their usefulness by founding a school under the above title. In this school will be taught practical truths and useful facts; the pedantry of science is to be avoided, and simple knowledge placed before the learner in an interesting and attractive way. Professor Mapes, the figriculturalist, seems to be the life and soul of this scheme, and we wish him success.