it being a V indication of the Existence and Attributes of that infinite BeING,to whom your Royal Highness hath, no lefs piously than justly,aforibed your great Royal FATHER's, and your Family's peaceable Accession to the Crown and Dignity of these Realms.

THAT the Blessings of the fame most merciful BEING may be perpetuated to your Royal Highness and all Yours, is the beardy Prayer of,

Most Illustrious. SIR, 1 bi Your Royal Highness's

moft humble obedient

Servant,

W. Derbai.

A

Preliminary Discourse,

CONCERNING

The Systemes of the Heavens, the Ha

bitability of the Planets, and a Plus rality of Worlds ; Useful for the reading of the following Book.

M

Y Physico-Theology having met with so quick a Sale as to come to a third Impression before the

Year was expired, but especially the follicitations of many Learned men, both known and hy Learned mom

unknown, have given me great encouragement to fulfil my promise, in sending abroad this other Part, relating to the Heavens: which should sooner have seen the light, but that I was minded not to interrupt the Reader's patience with many Notes (which I could not well avoid in my Phyfico-Theology, and which my Rough-Draught of this was burthened with) and therefore I threw the greatest part of them into the Text: which necessitated me to transcribe the whole. And when my Hand was in, I new-made some part of it, and added

many new Observations of my own, which I have lately made with some very good long Glasses I have in my hands; one of Campani's grinding; and others of English work, which exceed it; but especially one of Mr. Huygens's of about 126 feet, which few for goodness do surpass.

Of thefe Observations the Reader should have met with many more (and I believe some of my ingenious Friends do expect more) but that I lay under two inconveniences. One the want of an open free Horizon, my Habitation being surrounded much with Trees. The other, and indeed the chief, the want of a long Pole, of 100 or more feet, to raise my long Glass to such an height as to see the Heavenly Bodies above the chick Vapours, which much ob

; scure all Objects near the Horizon, especially when viewed with long and good Glasses.'. But as I have been at considerable expences already about these måtters, and this l'am informed would amount to 80 ore gol. I thought it much too great a burthen for the yearly Income of my Living.

some of my learned and ingenious Friends, I hope they will excuse me, and believe it to bemore my Calamity than Fault that I have done no more; especially among such Planets as have advantageously presented themselves as Saturn particularly hath, whose 5 or more Satellites it may be expected I have seen; but I could never reach bùt three of them, and they only when there were but few Vapours. And as for the Spots in Mars and Venus, and their Motion round their own Axes, I confess I have not yet had good Views of those Planers since I haye had my furniture of Glasses, by reason of the too great diftance of Mars from the Earth, and the proximity of Venus to the Sun, and of late the cloudy weather, and the fmall altitude which Venus hath above the Horizon. But if I can obo. tain a sufficient Apparatus, and God is pleased to grant me Life, Health,

and