To this Guard against the Cold, namely, of Fire and Cloathing; I hope the Reader will excuse me, if I take this Opportunity of adding some other Defensatives Nature, (or rather the great Author of Nature,) hath afforded these northern Regions: Such are their high Mountains, abounding, as Ol. Magnus saith, through all Parts; also their numerous Woods, which besides their Fire, do, with the Mountains, serve as excellent Screens against the Cold, piercing Air and Winds. Their prodigious Quantities of Minerals, and Metals, also afford Heat, and warm Vapours, Mineræ septentrionalium regionum satìs multæ, magnæ, diversæ, & opulentæ sunt, saith the same curious, and (for his Time,) learned Archbishop, l. 6. c. 1. and in other Places. And for the Warmth they afford, the Volcano’s of those Parts are in Evidence; as are also their terrible Thunder and Lightning, which are observ’d to be the most severe and mischievous in their metalline Mountains, in which large Herds of Cattle are sometimes destroy’d; the Rocks so rent and shatter’d, that new Veins of Silver are thereby discover’d; and a troublesome Kind of Quinsie is produc’d in their Throats, by the stench, and poisonous Nature of the sulphureous Vapours, which they dissolve, by drinking warm Beer and Butter together, as Olaus tells us in the same Book, Chap. 11.
To all which Defensatives, I shall, in the last Place add, the warm Vapours of their Lakes, (some of which are prodigiously large, of 130 Italian Miles in Length, and not much less in Breadth;) also of their Rivers, especially the Vapours which arise from the Sea. Of which Guard against severe Cold, we have lately had a convincing Proof in the great Frost, in 1708, wherein, when England, Germany, France, Denmark; yea, the more southerly Regions of Italy, Switzerland, and other Parts suffer’d severely, Ireland and Scotland felt very little of it, hardly more than in other Winters; of the Particulars of which, having given an Account in the Phil. Trans. Nᵒ. 324. I shall thither refer the Reader. But it seems this is what doth ordinarily befal those northern Parts; particularly the Islands of Orkney, of which the learned Dr. Wallace gives this Account: Here the Winters are generally more subject to Rain than Snow; nor doth the Frost and Snow continue so long here, as in other Parts of Scotland; but the Wind in the mean Time will often blow very boisterously; and it Rains sometimes, not by Drops, but by spouts of Water, as if whole Clouds fell down at once. In the Year 1680, in the Month of June, after great Thunder, there fell Flakes of Ice near a Foot thick. Wall. Account of Ork. Chap. 1. p. 4. From which last Passage I observe; That although in those Parts, the Atmosphere near the Earth be warm, it is excessively cold above; so as to freeze some of those Spouts of Water in their Descent, into such great, and almost incredible Masses of Hail. And whence can this Warmth proceed, but from the Earth, or Sea, emitting Heat sufficient to stave off the Cold above? Consult [Book II. Chap. 5. Note (c).]
[d] Sicut enim si innata sibi [i.e. Homini] aliqua haberat arma, illa ei sola semper adessent, ita & si artem aliquam Natura fortitus esset, reliquas sanè non haberet. Quia verò ei melius erat omnibus armis, omnibusque artibus uti, neutrum eorum à naturâ ipsi propterea datum est. Galen. de Us. Part. l. 1. c. 4.
[e] Concerning insensible Perspiration, Sanctorius observes, That it much exceeds all the Sensible put together. De Stat. Med. Aph. 4. That as much is evacuated by insensible Perspiration in one Day, as is by Stool in fourteen Days. Particularly, that, in a Night’s Time, about sixteen Ounces is commonly sent out by Urine, four Ounces by Stool; but above forty Ounces by insensible Perspiration, Aphor. 59, 60. That if a Man eats and drinks 8 l. in a Day, 5 l. of it is spent in insensible Perspiration, §. 1. Aph. 6. And as to the Times, he saith, Ab assumpto cibo 5 horis 1 l. circiter perspirabilis——exhalare solet, à 5a ad 12am 3 l. circiter; à 12a ad 16am vix selibram, Aph. 56.
And as to the wonderful Benefits of insensible Perspiration, they are abundantly demonstrated by the same learned Person, ubi supra; as also by Borelli in his second Part, De Mot. Animal, Prop. 168. who saith, Necessaria est insensibilis Transpiratio, ut vita Animalis conservetur.
[f] Animantium verò quanta varietas est? Quanta ad cam rem vis, ut in suo quæque genere permaneant? Quaram aliæ coriis tectæ sunt, aliæ villis vesticæ, aliæ spinis hirsutæ: plumâ alias, alias squamâ videmus obductas, alias esse cornibus armatas, alias habere effugia pennarum. Cic. de Nat. Deor. l. 2. c. 47.
[g] From Malpighi’s curious Observations of the Hair, I shall note three Things. 1. Their Structure is fistulous, or tubular; which hath long been a Doubt among the curious. Fistulosum [esse Pilum] demonstrant lustratio pilarum à caudâ & collo Equorum, &c.——præcipuè setarum Apri, quæ patentiorem ex fistulis compositionem exhibent. Est autem dictus Apri pilus Cylindricum corpus quasi diaphanum——fistularum aggere conflatum, & speciem columnæ striatæ præ se fert. Componentes fistulæ in gyrum situatæ in apice patentiores redduntur; nam hians pilus in geminas dividitur partes, & componentes minimæ fistulæ——libersores redditæ manifestantur, ita ut enumerari possunt; has autem 20, & ultra numeravi.——Expositæ fistulæ——tubulosæ sunt, & frequentibus tunicis transversaliter situatis, veluti valvulis pollent. Et quoniam Spinæ, in Erinaceis præcipui, &c. nil aliud sunt, quam duri & rigidi pili, ideo, &c. And then he describes the Hedgehog’s Spines, in which those Tubes manifestly appear; together, with medullary Valves and Cells; not inelegant, which he hath figur’d in Tab. 16. at the End of his Works.
That which this sagacious, and not enough to be commended Observer, took notice of in the Structure of Hair, and its Parity to the Spines; I have my self observ’d in some Measure to be true, in the Hair of Cats, Rats, Mice, and divers other Animals; which look very prettily when view’d with a good Microscope. The Hair of a Mouse, (the most transparent of any I have view’d,) seems to be one single transparent Tube, with a Pith made up of a fibrous Substance, running in dark Lines; in some Hairs tranversly, in others spirally, as in [Fig. 14, 15, 16, 17.] These darker medullary Parts, or Lines, I have observ’d, are no other than small Fibres convolved round, and lying closer together than in other Parts of the Hair. They run from the Bottom, to the Top of the Hair; and I imagine, serve to the gentle Evacuation of some Humour out of the Body; perhaps the Hair serves as well for the insensible Perspiration of hairy Animals, as to fence against Cold and Wet. In [Fig. 14, 16], is represented the Hair of a Mouse, as it appears through a small Magnifier; and in [Fig. 15, 17], as it appears when view’d with a larger Magnifier.
Upon another Review, I imagine, That although in [Fig. 14, 15], the dark Parts of the Pith seem to be transverse; that they, as well as in the two other Figures, run round in a screw-like Fashion.