But, as in Mathematics a limit is reached, beyond which the finite character of our intelligence does not permit us to _apply_ the Laws which we are well assured still prevail, so there is an outlying circle of practical activity which no Science can compass. The various tints of the autumn forest are probably the results of Mathematical arrangements of particles; but to how great an extent we shall be able to discover what precise arrangement produces a given shade of color, is doubtful. Some delicate varieties, at least, will always be beyond our definite apprehension. Whether we shall dine at one hour or another, whether we will wear gray or black, and innumerable other questions of specialty, do not come within the range of Scientific solution, and never can. So that when every domain of human concern is solidly established on a basis of Exact Science, there will still remain a field of indefinite extent, in which the Intuitive application of eternal Principles will furnish an unlimited activity for the Practical, AEsthetic, Imaginative, Idealistic, Artistic, and Religious faculties of Mankind. The task which Mr. Buckle set himself to accomplish was, in a marked sense, original and peculiar. Although several systematic attempts had been made in Europe, prior to his time, to investigate the history of man according to those exhaustive methods which in other branches of Knowledge have proved successful, and by which alone empirical observations can be raised to scientific truths, the imperfect state of the Physical Sciences necessarily rendered the execution of such an undertaking extremely defective. It was not, indeed, until the vast mass of Facts which make up the body of the various Sciences had been included within appropriate formulae, and until the elaborate Classification of Auguste Comte had separated that which was properly Knowledge from that which was not, with sufficient exactitude to answer the purposes of broad Generalization, and had established the relations of the different domains of intelligence, that such a work as the 'History of Civilization' was possible.