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rably. Sometimes they are nearer one another, sometimes farther asunder: Sometimes they are considerably broader, especially that nearest the middle; Sometimes as considerably narrower : Sometimes they both advance towards one Pole, and then recede towards the other opposite Pole. Of many of these Appearances I took Draughts
, and defigned to have enquired whether they bad certain Periods; but want of Health and Leisure prevented me.
And not only the Belts, but the Spots also of Jupiter vary greatly; I do not mean the Spots occasioned by the Shade of the Satellites, but such as are on the very Disk; which are formetimes of one Form, sometimes of another; and oftentimes none to be seen at all, altho’ the same Face of Jupiter should be towards us.
The last thing I shall mention is the Nebulole, which are those glaring
whitis Appearances, seen with our Telescopes in Andromeda's Girdle, Hercules's Back, Antinous's Foot, Orion's Sword, in the Centaur, Sagittary, &c. which appear through the Telescope fomewhat after the manner as Cor Cancri doth to the naked Eye.
These Nebulose I have often viewed with Glasses of very different Lengths, particularly that in pede Antinoi with Mr. Huygens's: but I confess that I could never discern what they are; neither indeed could I perceive any great Difference in their Appearances through a very good Glass of about 14 Foot, and others of 30 and 40 Foot, yea, Mr. Huygens's of 126.
But indeed the grand Obstacle to all my Views with Mr. Huygens's Glass was the Vapours near the Horizon, which not only obscured the Object, but caused so great a trembling and dancing thereof, as made it no less
difficult to be distinętly and accurately viewed, than a thing held in the hand is, when danced and faken backwards and forwards. By this means my Expectations from Mr. Huygens's Glass were frequently frustrated, excepting in Nights that were more than ordinarily serene and clear; which was commonly in such as were the most intensely frosty and cold.
Finding it therefore unlikely that I mould do much more with Mr. Huygens's Glass than I had done, I restored it to the Royal Society which lent it me, (and to whom Mr. Huygens bequeathed it by his last Will) contenting myself with the Views it had given me, and that I had discovered it to be an excellent Glass; which Dr. Hook, and some others of our best Judges, took to be good for nothing.
And now having given this Account of my Observations, and also foewed what hinder'd my compleating of them
(which may excite farther Enquiries, as well as serve to vindicate myself) I hall recommend these things to such as bave good Glasses, particularly to the Diligence and Accuracy of my very ingenious Friend, the Reverend Mr. Pound, into whose Hands the Royal Society have put that noble Bequest of Mr. Huygens, and who is so well accommodated for raising and using that Glass, as to have seen (among other considerable things, the five Satellites of Saturn; which I confess I could never reach, nor above three of them that I could be sure were Satellites: I say that I could be sure were such, because it is not very easy to distinguish which are Satellites, and which are small Telescopick Stars, which
very frequently shew themselves in a Glass of such Goodness as that is. I reinember that I once verily thought I had found out seven Satellites of Saturn with this very Glass of Mr. Huy
gens, foregularly were they placed in respect of Saturn. ' But when I came to examine them the following Nights, I found that there were really no more than two Satellites, the rest being small Fixt Stars. But Mr. Pound's Skill and ExaEtness in such Observations is, I know, so great, (and I may add that of my fagacious Friend Dr. Halley too, who I hear hath seen the same) that I do not say this by way of Caution to them, although it may serve as such to many others.
And now for a Close, I shall take this Opportunity of publickly owning, with all Honour and Thankfulness, the generous Offer made me by some of my Friends, eminent in their Stations, as well as Skill and Abilities in the Laws, who would have made me a Present of the May-pole in the Strand, (which was to be taken down) or any other Pole I thought convenient for the Management of Mr. Huygens's Glass.