moveth them thus, at proper Times, to fly from a Place that would obftruct their Generation, or not afford convenient Food for them, and their Young, and betake themfelves to another Place, affording all that is wanting for Food or Incubation.

And this leads me to another Thing remarkable in this Act of Migration; and that is, That thofe unthinking Creatures fhould know what Way to fteer their Courfe (c) and whither to go. What but the great Creator's Inftinct fhould ever move a poor foolish Bird, to venture over vaft Tracts of Land, but especially over large Seas? If it should be faid, That by their high Afcents up into the Air, they can fee cross the Seas; yet what should teach or perfuade them, that that Land is more proper for their Purpofe, than this? That Britain, (for Inftance,) fhould afford them better Accommodations than Egypt (d), than the Canaries, than Spain,

or

(c) Quis non cum admiratione videat ordinem & politiam peregrinantium Avium, in itinere, turmatim volantium, per longos terrarum & maris tractus abfque Acu marinâ?- -Quis eas certum iter in aëris mutabili regione docuit ? Quis praterite figna, futura via indicia; quis eas ducit, nutrit, & vite neceffaria minißrat! Quis infulas & hofpitia, illa, in quibus victum reperiant, indicavit; modumque ejufmodi loca in peregrinationibus fuis inveniendi? Hac fane fuperant hominum captum & induftriam, qui non nifi longis experientiis, multis itinerariis, chartis geographicis, acús magnetica beneficio,

-ejufmodi marium & terrarum tractus conficere tentant & audent. Lud. de Beaufort. Cofmop. divina Sect. 5. c. 1.

(d) I inftance particularly in Egypt, becaufe Mr. Willughby thinks Swallows fly thither, and into Ethiopia, &c. and that they do not lurk in Holes, or under Water, as Olaus Magnus Reports. Vid. Ornith. L. 2. c. 3. But Etmuller puts the Matter out of doubt; who faith, Memini me plures, quàm quas Medimnus caperit, Hirundines arete coacervatas intra Pifcina cannas, fub glacie prorfus ad fenfum exanimes pulfantes tamen, reperiiffe. Etmuller Differt. 2. c. 10. §. 5. This as it is like what Ol. Magnus faith, fo is a Confirmation of it, The Archbishop's Account is, In Septentrionalibus aquis fapius cafu Pifcatoris extrahuntur Hirundines, in modum congior

› merata

or any of those many intermediate Places over which fome of them probably fly.

And lastly, to all this, let us briefly add the Accommodations thefe Birds of Paffage have, to en able them to take fuch long Flights, viz. the Length of their Wings, or their more than ordinary Strength (e) for Flight.

merata maffa, qua ore ad os, & alâ ad alam, & pede ad pedem poft principium autumni fefe inter cannas defcenfura colligarunt. Maja autem illa per imperitos adolefcentes extracla, arque in aftuaria portata, caloris acceffu Hirundines refoluta, volare quidem incipiunt, fed exiguo tempore durant. Ol. Mag. Hift. L. 19. c. 20.

Since my penning this Note, we had, at a Meeting of the Royal-Society, Feb. 12. 1712-13. a farther Confirmation of Swallows retiring under Water in Winter, from Dr. Golas, a Perfon very curious in thefe Matters; who fpeaking of their Way of Fishing in the northern Parts, by breaking Holes, and drawing their Nets under the Ice, faith, that he faw fixteen Swallows fo drawn out of the Lake of Samrodt, and about Thirty out of the King's great Pond in Rafireilen, and that at Schlebitten, near an Houfe of the Earl of Dohna, he faw two Swallows just come out of the Waters, that could fcarce ftand, being very wet and weak, with their Wings hanging on the Ground: And that he hath obferv'd the Swallows to be often weak for fome Days after their Appearance.

(e) As Swallows are well accommodated for long Flights, by their long Wings, fo are Quails by the Strength of their pettoral Mufcles, by the Breadth of their Wings, c. For Quails have but fhort Wings for the Weight of their Body; and yet they fly from us into warmer Parts, against Winter, and to us in Spring, croffing our Seas. So divers Travellers tell us they cross the Mediterranean twice a Year, flying from Europe to Africa, and back again: Thus Bellonius in Mr. Willughby, faith, When we fail'd from Rhodes to Alexandria of Egypt, many Quails flying from the North towards the South, where taken in our Ship; whence I am verily perfua ded, that they fhift Places: For formerly also, when I fail'd out of the Ifle of Zant to Morea, or Negropont, in the Spring Time, I had obferv'd Quails flying the contrary Way, from South to North, that they might abide there all Summer. At which Time alfo, there were a great many taken in our ships Ornith. p. 170.

BA ĐỐI ĐẦU VỚC HOA P. IV.

Of the INCUBATION of Birds.

A

1

Nother Thing relating to the State of this Tribe of Animals, is their Incubation. And first, the Egg it felf deferves our Notice. Its Parts within, and its crufty Coat without, are admirably well fitted for the Bufinefs of Incubation. That there fhould be one Part provided for the Formation of the Body (a), before its Exit into the World, and another for its Nourishment, after it is come into the World, till the Bird is able to fhift for, and help it felf; and that these Parts fhould be fo accurately brac'd, and kept in due Place (b), is certainly a defign'd, as well as curious Piece of Workmanship.

(a) The Chicken is form'd out of, and nourish'd by the White alone, till it be grown great. The Yolk ferves for the Chicken's Nourishment, after it is well grown, and partly also after it is batch'd. For a good Part of the Yolk remains after Exclufion, being receiv'd into the Chicken's Belly; and being there referv'd, as in a Store-house, is by the [Appendicula, or Ductus inteftinalis, as by a Funnel, convey'd into the Guts, and ferves inftead of Milk, &c. Willugh. Ornith. L. 1. c. 3. Ipfum ani→ mal ex albo liquore Ovi corporatur. Cibus ejus in luteo eft." Plin. L. 10. C.. 53.

Ariftotle faith, The long sharp Eggs bring Females; the round ones, with a larger Compass at the sharper End, Males. Hift. An. L. 6. c. 2. After which, he tells of a Sott at Syracuse, that fate drinking fo long, till Eggs were hatch'd; as also of the Custom of Egypt, of hatching Eggs in Dunghills.

(6) As the Shell and Skin keep the Yolk and two Whites together; fo each of the Parts, (the Yolk and inner White at leaft,) are feparated by Membranes, involving them. At each End of the Egg is a Treddle, fo call'd, because it was

Book VH. And then as to the Act it felf, of Incubation, What a prodigious Inftinct is it in all, or almost all the feveral Species of Birds, that they, and only they, of all Creatures, fhould betake themselves to this very Way of Generation? How should they be aware that their Eggs contain their Young, and that their Production is in their Power (c)? What fhould move them to betake themfelves to their Nefts, and there with Delight and Patience to a-. bide the due Number of Days? And when their Young are gotten into the World, I have already fhewn how admirable their Art, their Care, and Zrogyn is in bringing them up until, and only until, they are able to fhift for themselves.

formerly thought to be the Sperm of the Cock. But the Ufe of thefe, (faith Dr. Harvey in Willugh. Ornith. c. 3.) is to be as 'twere, the Poles of this Microcofm, and the Connections of all the Membranes twifted and knit together, by which the Liquors are not only conferv'd, each in its Place, but do also retain their due Pofition one to another. This, although in a great Measure true, yet doth not come up to what I have my felf obferv'd; for I find, that thefe Chalaza, or Treddles, ferve not barely to keep the Liquors in their Place, and Podition to one another; but alfo to keep one and the fame Part of the Yolk uppermoft, let the Egg be turn'd, nearly which way it will; which is done by this Mechanifm: The Chalaza are fpecifically lighter than the Whites, in which they fwim; and being brac'd to the Membrane of the Yolk, not exactly in the Axis of the Yolk, but fomewhat out of it, caufeth one Side of the Yolk to be heavier than the other; fo that the Yolk being by the Chalaza made buoyant, and kept fwimming in the Midft of two Whites, is by its own heavy Side kept with the fame Side always uppermoft which uppermoft Side I have fome Reafon to think, is that, on which the Cicatricula lies; that being commonly uppermoft in the Shell, efpecially in fome Species of Eggs more I think than others.

(c) All Birds lay a certain Number of Eggs, or nearly that Number, and then betake themfelves to their Incubation; but if their Eggs be withdrawn, they will lay more. Of which, fee Mr. Ray's Wif, of God, p. 137.

And

And laftly, when almoft the whole Tribe of Birds, do thus by Incubation, produce their Young, it is a wonderful Deviation, that fome few Families only, fhould do it in a more novercal Way (d), without any Care or Trouble at all, only by laying their Eggs in the Sand, expofed to the Heat and Incubation of the Sun. Of this the Holy Scripture it felf gives us an Inftance in the Oftrich: Of which we have an Hint, Lam. iv. 3. The Daughter of my People is become cruel, like the Oftriches in the Wilderness. This is more plainly expreffed in Job xxxix. 14, 15, 16, 17. [The Oftrich] leaveth her Eggs in the Earth, and warmeth them in the Duft, and forgetteth that the Foot may crush them, or that the Wild-Beast may break them. She is hardened against ber Young ones, as though they were not hers: Her Labour is in vain, without Fear. Because God hath deprived her of Wisdom, neither hath be imparted unto her Understanding. In which Words I fhall take notice of three Things, 1. Of this anomalous Way of Generation. It is not very ftrange, that no other Incubation but that of

(d) The Tabon is a Bird no bigger than a Chicken, but is faid to lay an Egg larger than a Goofe's Egg, and bigger than the Bird it felf. These they lay a Yard deep in the Sand, where they are hatch'd by the Warmth of the Sun; after which they creep out, and get to Sea for Provifions. Navarett's Account of China in Collect. of Voyages, Vol. 1. This Account is in all Probability borrow'd from Nieremberg, or Hernandez, (that copy'd from him,) who call this Bird by the Name of Daie, and its Eggs Tapun, not the Bird it felf, as Navarette doth. But my Friend Mr. Ray faith of it, Hiftoria ifthac proculdubio fabulofa e falfa eft. Quamvis enim Aves nonnulla maxima ova pariunt, ut v. g. Alkæ, Lomwiæ, Anates, Arcticæ, &c. hujufmodi tamen unum duntaxat, non plura ova ponunt antequam incubent: nec ullam in rerum naturâ avem dari exiftimo cujus ova albumine careant. Cum Albumen precipua ovi pars fit, quodque primum fœtui alimentum fubminiftrat. Raii Synop. Av. Method. p. 155.