The various definitions of the same subject which prevail, originate in the caprice, or partial, or profound knowledge the definer may have of his subject. It seems to be admitted by logicians, that an author has a right to give whatever provisional definition he pleases of his terms. But having once given them, perspicuity requires that he should adhere to them. Any new sense in which a term is employed should be specially defined. In discoursing on an ordinary subject, as the right of public assembly,--such words as perception, conception, apprehension, might be used reciprocally, but in a dissertation on metaphysics each requires restriction in use and precision in purport. Often genius strikes out new relations of words. In recent political debates, Mr. Cobden resorted with new force and point to a charge of rashness against ministers: he showed that rashness consisted more frequently in inaction than action. He is rash who stands surrounded by the elements of danger without taking; any precaution against the contingencies of peril; he is rash who does not take advantage of the calm, to repair his shattered rigging; he is rash who looks not out for a proper supply of water until the conflagration is raging around him; and more rash than all is he who exercises no provident care for supplying a nation with food, but waits for the pressure of famine and the perils of starvation. At the last soiree of the Leeds Mechanics' Institution, Mr. Dickens referred to ignorance, commonly considered as a passive negation, and placed it in the light of a power. 'Look where we will, do we not find ignorance powerful for every kind of wrong and evil? Powerful to take its enemies to its heart and strike its best friends down--powerful to fill the prisons, the hospitals, and the graves--powerful for blind violence, prejudice, and error in all their destructive shapes.' The variations which not only common but technical terms undergo, is a considerable source of perplexity in reasoning. Mr. Mill cites the instance of the term felony. No lawyer will undertake to tell what a felony is otherwise than by enumerating the various kinds of offences which are so called. Originally, felony denoted all offences, the penalty of which included forfeiture of goods; but, subsequent Acts of Parliament have declared various offences to be felonies without enjoining that penalty, and have taken away the penalty from others which continue still to be called felonies, insomuch that the acts so called have now no property whatever in common, save that of being unlawful and punishable. This inattention to precision in terms has arisen not among the vulgar, but among educated English lawyers.