Turn next to the Abstract-Concrete sciences.  On the application of the simplest of these, Mechanics, depends the success of modern manufactures.  The properties of the lever, the wheel-and-axle, etc., are recognised in every machine, and to machinery in these times we owe all production.  Trace the history of the breakfast-roll.  The soil out of which it came was drained with machine-made tiles; the surface was turned over by a machine; the wheat was reaped, thrashed, and winnowed by machines; by machinery it was ground and bolted; and had the flour been sent to Gosport, it might have been made into biscuits by a machine.  Look round the room in which you sit.  If modern, probably the bricks in its walls were machine-made; and by machinery the flooring was sawn and planed, the mantel-shelf sawn and polished, the paper-hangings made and printed.  The veneer on the table, the turned legs of the chairs, the carpet, the curtains, are all products of machinery.  Your clothing—­plain, figured, or printed—­is it not wholly woven, nay, perhaps even sewed, by machinery?  And the volume you are reading—­are not its leaves fabricated by one machine and covered with these words by another?  Add to which that for the means of distribution over both land and sea, we are similarly indebted.  And then observe that according as knowledge of mechanics is well or ill applied to these ends, comes success or failure.  The engineer who miscalculates the strength of materials, builds a bridge that breaks down.  The manufacturer who uses a bad machine cannot compete with another whose machine wastes less in friction and inertia.  The ship-builder adhering to the old model is out-sailed by one who builds on the mechanically-justified wave-line principle.  And as the ability of a nation to hold its own against other nations, depends on the skilled activity of its units, we see that on mechanical knowledge may turn the national fate.

On ascending from the divisions of Abstract-Concrete science dealing with molar forces, to those divisions of it which deal with molecular forces, we come to another vast series of applications.  To this group of sciences joined with the preceding groups we owe the steam-engine, which does the work of millions of labourers.  That section of physics which formulates the laws of heat, has taught us how to economise fuel in various industries; how to increase the produce of smelting furnaces by substituting the hot for the cold blast; how to ventilate mines; how to prevent explosions by using the safety-lamp; and, through the thermometer, how to regulate innumerable processes.  That section which has the phenomena of light for its subject, gives eyes to the old and the myopic; aids through the microscope in detecting diseases and adulterations; and, by improved lighthouses, prevents shipwrecks.  Researches in electricity and magnetism have saved innumerable lives and incalculable property through the compass; have subserved many arts by the electrotype; and now, in the telegraph, have supplied us with an agency by which for the future, mercantile transactions will be regulated and political intercourse carried on.  While in the details of in-door life, from the improved kitchen-range up to the stereoscope on the drawing-room table, the applications of advanced physics underlie our comforts and gratifications.