_The buoyancy of the human body_ is another point in the history of Drowning, which has occasioned much discussion; and in solving the problem, so highly important in its forensic relations, _whether a body found in the water, had been drowned, or thrown in after death_, it has been considered by some physiologists as capable of affording a certain degree of presumptive evidence, although we are inclined to attach but little or no importance to such an indication. The specific gravity of the human body, under ordinary circumstances, is very little greater than that of fresh water, so small indeed is the difference that, when the lungs are inflated, a man will float[37] with little or no effort, if he have sufficient self possession, and does not attempt to raise too great a portion of his body out of the sustaining fluid;[38] but, when the air of the lungs is expelled, and probably, at the same time, a certain quantity of water is taken into the stomach,[39] the body becomes specifically heavier, and the victim sinks. It may be assumed as a general rule, that no newly drowned body floats, although many facts have been adduced in support of a contrary opinion; the naval custom of loading the dead bodies with weights, before they are consigned to a watery grave, is not for the purpose of sinking the corpse, but for preventing its rising after the process of putrefaction has commenced. The period during which a body will remain at the bottom cannot be very accurately determined, as the change does not take place until a sufficient quantity of air be generated to buoy it again to the surface; in the melancholy instance of the loss of the Royal George, the dead bodies were observed ascending to the surface of the sea, on or about the fifth day. The general position of a body which has thus risen, provided there be no external or adventitious circumstances to change it, is such, that it floats nearly immersed, the face, arms, and legs hanging downwards, and the loins being uppermost; this is the form which the body must mechanically and hydrostatically assume, if the sustaining power of generated air be, as it generally will, in the cavity of the abdomen, where putrefaction is more likely to commence; for the head and limbs are generally[40] specifically heavier than water, while the trunk, especially if inflated with air, is somewhat lighter.