though a pound lump of that ſame metal is ſo long able to reſiſt their violence. That theſe particles of ſcent are of an equal (exactly equal) ſpecific gravity with the particles of the air, is demonftrated by the falling and riſing of them in juſt proportion to it. I have often ſmiled at haſty Huntſmen, to hear them rating and curſing their dogs (that yeſterday were the beſt in England) for galloping and ſtaring, with their noſes in the air, as if their game was flown; for often does it happen that it is in vain for them to ſeek after the ſcent in any other place, the increaſing weight of that fluid element having wafted it over their heads. Though, even at fuch a ſeaſon, after the firſt mettle and fury of the cry is ſomething abated, the more ſteady Beagles may make a ſhift to pick it out by the particles left by the bruſh of her feet, efpecially if there be not a ſtrong, drying, exhaling wind to hurry theſe away after the reſt. This often happens in a calm, gentle, ſteady froſt, when, as I conceive, the purity, coldneſs, or, perhaps, the nitre of the air, ſerves to fix and preſerve the few remaining particles, that they do not eaſily corrupt. At ano-
