The great variety of proportions presented by the human body causes much difficulty in determining with precision what are the best. The difficulty becomes quite insurmountable if we attempt to assign precise dimensions to the details of configuration or to minute parts. Many circumstances are opposed to the exactness of these measures. Even in the same person, one part is rarely in all respects similar to the corresponding part; we are taller in the morning than in the evening; and the proportions change at different periods of life. In different individuals, the differences are still more evident. Moreover, habits, professions, trades, all unite to oppose regularity in the proportions. It has farther been observed that, in the conformation of woman, both as regards the whole and as regards the various parts, nature still more rarely approaches determinate proportions than in man. It is remarked by Hogarth, whose views I now abridge, that in society we every day hear women pronounce perfectly correct opinions as to the proportions of the neck, the bosom, the hands, and the arms of other women, whom they have an interest in observing with severity. It is evident that, for such an examination, they ought to be capable of seizing, with great precision, the relation of length and thickness, and of following the slight sinuosities, the swellings, the depressions, almost insensible and continually varying, at the surface of the parts observed. If so, it is certainly in the power of a man of science, with as observing an eye, to go still farther, and conceive many other necessary circumstances concerning proportion. But he says: "Though much of this matter may be easily understood by common observation, assisted by science, still I fear it will be difficult to raise a very clear idea of what constitutes or composes the utmost beauty of proportion.... We shall soon find that it is chiefly to be effected by means of the nice sensation we naturally have of what certain quantities or dimensions of parts are fittest to produce the utmost strength for moving or supporting great weights, and of what are most fit for the utmost light agility, as also for every degree, between these two extremes." After some illustrations of this, which naturally leave the method very vague, he adds: "I am apprehensive that this part of my scheme, for explaining exact proportion, may not be thought so sufficiently determinate as could be wished." So that Hogarth's method as to proportions, both general and particular, reduces itself to the employment of the eye and the nice sensation we have of quantities or dimensions. But the Greek artists had not only done what Hogarth thus vaguely speaks of, but advanced much farther; and indeed all that has been done on this important subject belongs rather to the history of art than that of nature.