LETTER XCI.

SIR,

The Observatory, No. 17th, 1702.

My Lord Aston mistook my figures. If instead of page 174, in Mr Fontenell's Histoire del Academie de Sciences, you had lookt 5 pages forward, viz. to 179, you would have found Mr Cassini's remarks on my letter to Dr Wallis. You must be wary how you read them, for they are pure paralogisms, tho he has light upon truth at the conclusion which does not follow from the premises. I have wrote a letter to Sir C. A. to shew the faults of his figures, and the real effects of the parallaxes of the earth's orbe in changeng the apparent places of the fixed stars. Tis too long to be transcribed; but I come sometimes to London, and if wee may meet there by appointmt. it shall be shewed you, and you will, I hope, apprehend that business clearly. If when you write

to my lord, you please to present him my re

spects, you will oblige

Your very humble servant,

JOHN FLAMSTEED.

To Wm. Aston, Esq. at ye Surgeons Armes, next dore to ye Goat Tavern, in Bloomsbury, these present, London.

LETTER XCIII.

MY LORD,

The Observatory, Feb. 20, 1702-3.

I HEARTILY beg yr lordship's pardon for haveng neglected to cause the papers I promised to be copyd and sent. My elder servant has left me about 4 months agone to teach mathematicks in London. My younger has been continually employed either in my new Lunar Tables, ye laborious worke of ye fixed stars, or in ye care of a couple of young gentlemen, noblemen's sonns, yt are now goeng to the Indies. I have had but indifferent health my 'selfe, which has forced me to imploy all the time I could gaine in my business, and trust the good nature of my frends, rather than neglect what was under my hands. But on yr lordship's admonition, I have caused him to copy so much of a letter I wrote to a frend relating to this business, as I hope will satisfie

you that Mr Cassini's remarkes are besides the business. You will wonder that the Academy of Sciences should suffer them to pass into the publick; and I should have done so too, but that I considered his designe was to shew a way to represent ye parallaxes of the orb and ye starrs, by makeng the poles of the eclyptick and equator to move in little circles round the fixed poles of those circles. The contrivance is pretty for those who are fond of the papall systeme, but without ground. I have shewed in the latter pte of this letter (my servant has copied) that these circles will not serve, and that the effects or result of the earth's motion will not be solved by any such supposition.

But considering further, that to those who understand the earth's motion, the misrepresentations of Mr Cassini would be obvious on the first consideration, to others my reflections on his remarks would be useless, and that publishing them would certainly engage me in a controversy that would devour my time, and hinder me from prosecuting the business under my hands, for which all the time I have is not sufficient, and for which I want ye help of some skilfull persons; haveng satisfied my frend and

some skilfull persons in town, I have determined to take no notice of these remarkes of Mons. Cassini's at present, and to publish what I have wrote on this subject togeather with ye large Catalogue to which it belongs properly, and where it will be necessary to solve severall appearances in their meridional heights, not hitherto taken notice of.

In the meane time, if yr lordship as you goe to London any time this year shall please to crosse the Thames to Greenwich, giving me notice aforehand, I shall attend you here, and shew you that which will satisfie you that Mr Cassini knows nothing of the business he pretends to, or if he does, wilfully misrepresents it; and at the same time, you will see new mapps of the heavens, wherin the figures of the globes are all restored to ye ancient formes of Hyparchus. Or if yr lordship pleases to let me know where I may attend you in London, any time this spring, I shall waite on you with a copy of the remaining parte of my letter: only I desire you will not suffer what I have given you to be copied or sent abroad, least you thereby engag me unseasonably in a con