Mr Livingston to attend with you on the part of this Province I am [Indorsed] Sir your most obed Humble Servant GEO. CLARKE. To the Honorable CADWALLADER COLDEN Esq George Graham to Mr. Collinson. MR. COLLINSON. It has been found from repeated experiments that this Gentlemans Ingenious contrivance of a Quadrant will not answer expectation when reduced to practice. The late Dr Hook of Gresham College had the same thought above 70 years ago, which induced Mr. Flamstead to Screw the outward Limb of his large Mural Arck of 71⁄2 feet radius which he made at the observatory at Greenwich in y year 1689. In a little time he found the Screw Work dammaged by wearing to that degree that render'd it less exact than the divisions upon the face of the Limb. Of all Sorts of Motions there are none that have a greater friction than a Screw, it communicates Motion only by sliding, and whether with or without oil it wears very much if any considerable force is upon it, or if it be frequently used. It will do very well in the Nature of a Micrometer, where the pressure is Small and the Motion of the Male or female Screw is in a direct line; but in a circle or Quadrant the radius would by the wearing of the Screws, be continually altering. The Quadrants so much and so unjustly, commended by Leadbetton are still worse, being imperfect from the very Nature of their Construction, which consists of a pendulum moving wheelwork to enlarge the Scale. Besides the friction of the axis of the pendulum in its holes, the wheel work to be moved by the pendulum prevents its finding the perpendicular; so that by this contrivance when the Index shows you to Seconds of a degree, the pendulum itself may be several minutes from the perpendicular. If any Instruments should be wanted for taking the Latitude, or finding a Meridian and continuing its direction to any distance, I know of no person whatever that makes them to that degree of exactness as Mr. Sisson Mathamatical Instrument Maker in the Strand. If any Sort should be desired, if it happens in my time, I should very readily give him my opinion with relation to the execution of them. If what I have said may afford any Satisfaction to your friend it will be a pleasure to In returning my thanks for your obligeing present (wch I much admire) It gives mee a pretence to Trouble you with a few Lines & to enclose Mr Grayhams opinion of y Scheme for a Quadrant his remarks Seeme to mee very Rational but as I am not Skilled in those matters shall Submitt them to your Better Judgement. t Wee are in hopes you will oblige the Curious wth the other of the Histo" of the Five Nations the first gave such an Idea of the Nature & Constitutions of them wch are very informeing & Entertaining the Second no Doubt will Further Illustrate that matter and very possible the reader may reape some Benefit from its Delay by Some Aditions that you maybe able to make both as to the Increase & advantages of trade of Further Discoveries & Phaps some more peices of Natural Hist Tretises of this kind where they may be rely'd on are much in Request & Demand Here-and if you don't choose to print it y' self there is those In London will Readyly do It and as the First part is quite out of print, what if It Suffer a Revisal or Aditions & Both come out together that would make the Work very compleat-one thing as an Englishman I beg leave to add that whilst We are most agreeable Informed of the progress & Increase of Trade no hints may be given to the French to our Disadvantage who are Ever on the Watch-I Rely on your Candor & Goodness to Excuse these Hints-I wish I could otherwise recommend myself to y Esteeme then by offering you my ServicesIf I can do you any it will be a Real pleasure to y Sincere Friend I beg y' acceptance of a Small Tract on the Yellow Feaverit has been well Received here Mr Alexander will send it to you. P. S. P. COLLINSON. If an Ingenious Man and a great teacher unto Nature Named John Bartram of Pensilvania should wait on you please to give him what Information you can on those things he may inquire of You, he has been a Considerable Traveller in y' World and Is employed by a Sett of Noblemen & others to Colect Seeds & Curiosities for themyr P. C. [Indorsed] To Doc COLDEN Albany Cadwallader Colden to Peter Collinson. I receiv'd yours of the 5th of March at Providence in New England where I now am in Execuition of a Commission under the Great Seal to me & others for settling the Boundary Between the Province of Massachusets Bay & Colony of Rhode Island. You have been so very kind in answering what I desired by Mr Alexander that I think it my Duty to acknowledge the obligation without delay No doubt your desire to promote any thing that may be generally usefull has made you take the trouble you have allready taken & it makes me presume that you will not be displeased with my adding more upon the same subject. We have but too much reason to be sensible in the great Defects of the Geography of North America not withstanding that in many cases it must be useful and in some necessary to our Ministers to have a true Account of our Coasts & of the most considerable plans on it as well as our Merchants. The design of my thinking & writing on the Composition of a New Kind of Quadrant was in order to discover whether one could be made portable & at the same time sufficiently accurate so as that any curious Gentleman may as he travels from place to place without much trouble correct the Geography of the plans through which he passes the usefullness of the Design I hope will excuse the (perhaps fruitless) trouble that I give you in the pursuit of it. Tho' Mr Graham has fully convinced me that the Method by a Screw work will not succeed in practise yet what he adds that Dr Hook & Mr Flamstead had formerly intertain'd the same thoughts gives me the vanity to observe that my error is not greater than what Gentlemen of Great Judgement in those matters have likewise fallen into I wrote last Fall to Mr Alexander of the Advantages which I thought would arise by dividing a circle by some kind of clock work above what the common Quadrants or Sextants have in the Common Method of Dividing the Limb but that letter came too late to his hands to go by the ships to London. I shall desire Mr Alexander to forward it to you if in his Judgement it contains any thing that deserves to be communicated that tho' I may not have hit upon a good method of pursueing that design it may give hints where some skillful person may: for I have often observ'd that a blundering understanding has sometimes given an accedental hint that a Skillfull person has improved to great advantage. I shall in as few words as I can add something to this purpose which has occurr'd to me since I receiv'd yours It is this let a Brass circle of Sufficient Solidity & Diameter be made but that towards the limb it be thinn'd off so as to be no thicker than the wheel of a Watch & this limb indented with teeth as small as those of a Watch wheel & that proper sights be fixed to this limb Now if to this limb Watch work be applied with indexes properly adopted to mark the degrees & minutes thus Indented the most minute alteration of the position of the circle may be made sensible to the eye by the Indexes In this I suppose that Artists know or can discover a Mechanical method by which the limb of the circle can be equally & accurately indented Now Mr. Graham understands every thing of this kind so perfectly that I am satisfied he can upon the once reading of what I wrote last fall together with this hint with great certainty say whether it be practicable or not. As my Business has at several times carried me over a great part of North America I might have had many opportunities of Correcting the Georgraphy of this Country with such an Instrument as I propose & some other may after this have the like I am told that when the French Ministers send any officer to Distant Countries they furnish him with Instruments for observing accurately their Scituation tho his Business be of a different nature & by that means have obtain❜d a knowledge of what we are shamefully ignorant I mean of our own Colonies in America They thereby prevent us in many useful designs & are better Judges of any proposals made to them relating to foreign Countries than we can be This furnishing of Skillfull persons with the necessary Instruments obtains a knowledge to the publick at a small expence & yet this expense is often too great for a private person who has no greater interest in it than satisfying his curiosity You have S engaged my thoughts on revising the History of the Indian Nations a thought which I had entirely laid a side by reason that my Business carrying me from home allmost three quarters of the year my |