Serpents are provided with Tails of different Length and Size; these also are necessary to adjust their Motion, and guard them against Stimulation of Flies. In winged Serpents, the Tail serves as a Rudder to govern them in flying through the Air; and, in the marine Serpents, they serve as Oars. But another says, the flying of a Bird, in effect, is quite a different Motion from the sailing of a Ship: Birds don’t vibrate their Wings towards the Tail, as Oars are struck towards the Stern, but waft them downward; nor does the Tail of the Bird cut the Air at right Angles as the Rudder does the Water, but it is disposed horizontally, and preserves the same Situation what way soever the Bird turns[3]. Footnote 3: _Borelli._ They are painted with variety of Colours, as red, black, white, brown, green; the Composition of these, in some of their Garnitures, forms Beauties exquisitely fine. Some of them have very little Eyes, others large ones: Some wound with their Teeth, others with the Tail that terminates in a Sting, which is an Apparatus in the Body of certain Insects like a little Lance, serving them as a Weapon of Offence. Mention is made by Historians of harmless Serpents, and of Persons who have tamed Serpents, and whose Hair has been kissed by a tame Dragon, and which, with its Tongue, gently lick’d its Master’s Face[4]. Footnote 4: _Raii Synopsis. Ælian. Hist._ The Serpent seems to be one of the distinguished Favourites of the Air, seeing it subsists by aerial Food all Winter; that is, in those Regions where it dare not turn Ranger. Sleep is the Nurse of Nature, a Nurse that greatly indulges the animal Spirits, and, by arresting voluntary Motion, prevents their daily Consumption, and, at the same time, allows the perpetual Motion of the Arteries, Veins, Heart. We know but little of the real peculiar Nature of what we call Air, only that it is the most heterogeneous Body in the World, a kind of secondary Chaos, being a Compound of minute Particles of various Kinds, Earth, Water, Minerals, Vegetables, Animals, _&c._ collected either by solar or artificial Heat. These Particles together constitute an Appendage to our Earth, called Atmosphere; or that thin, elastick, fluid Mass, wherein we live, move, and have our being; which Air we continually receive, and expel by Respiration, and no Animal can live, or Vegetable grow without it. Thus Serpents inclosed in the Receiver, are immediately (I may say) starved when deprived of Air, which is their only Winter-Food.—_N. B._ Whatever is put in a Receiver so exhausted, is said to be put _in Vacuo_: Animals that have two Ventricles, and no _Foramen Ovale_, as Birds, Dogs, Cats, Mice, die in it in less than half a Minute; a Mole died in one Minute; a Bat lived seven or eight; Insects, as Wasps, Bees, Grashoppers, seem dead in two Minutes[5]. Footnote 5: _Derham._