as Mr. Babbage’s volume, could be made to diffuse more happiness and real enjoyment than the right understanding and application of the principles illustrated in its pages.  Theory and practice, proposition and proof, go hand in hand through every chapter; and all this has been done in such concise language, and with such avoidance of technical terms as to be intelligible to readers of any grade.  The author is a professor of mathematics at Cambridge, but his honours are not vaunted in fine unintelligibilities:  he writes of common things in a common way, and not, like Hudibras, who told the clock by algebra, or, like the lady in Dr. Young’s Satires, who drank tea by stratagem.  Would that all professors had written in the same vein.  Then, learning would not have been so mixed up with the mysticism of the cell and the cloister, nor the evils of ignorance have so long retarded the happiness of mankind:  for, “learning,” observes one of the greatest moralists of his day, “once made popular is no longer learning; it has the appearance of something which we have bestowed upon ourselves, as the dew appears to rise from the field which it refreshes.”

The origin of Mr. Babbage’s work will best explain its practical worth.  He considers it as one of the consequences that have resulted from the Calculating Machine, the construction of which he has been long superintending.  Having been induced during the last ten years to visit a considerable number of workshops and factories, both in England and on the Continent, for the purpose of endeavouring to make himself acquainted with the various resources of mechanical art, he was insensibly led to apply to them those principles of generalization to which his other pursuits had naturally given rise.  It should be observed, that he has not attempted to offer a complete enumeration of all the mechanical principles which regulate the application of machinery to arts and manufactures, but he has endeavoured to present to the reader those which struck him as the most important, either for understanding the action of machines, or of enabling the memory to classify and arrange the facts connected with their employment.  Or, a still more lucid explanation of the object of the volume is—­“to point out the effects and the advantages which arise from the use of tools and machines;—­to endeavour to classify their modes of action;—­and to trace both the causes and the consequences of applying machinery to supersede the skill and power of the human arm.”

To dwell upon the interest of these inquiries in a manufacturing country like our own, would be a waste of time; as it would be to question their full appreciation by the, par excellence, useful classes.  Yet, a lamentable indifference to manufacturing processes pervades wealthier persons.  Mr. Babbage observes, “those who possess rank in a manufacturing country can scarcely be excused if they are entirely ignorant of principles whose developement has produced its