George Street Hanover Square Octr: 15. 1786.
I thank you for the loan of the Memoirs of the American Academy of Arts and Sciences, they have afforded me much entertainment particularly those written by Governor Bowdoin on the structure of the Heavens, and on Light; I feel myself happy that my Countrymen are inspired with a thirst after knowledge, and to see them emulating the Nations of Europe in the cultivation of the Arts and Sciences.
As you have done me the honor to desire my opinion of the plates in this work, I will give  to you without reserve; I think them well Engraved, much better than I should have expected, as there was no person that knew much of that Art, in the State of Massachusetts when I left it; but there is a total want of the knowledge of Perspective in every part of them; It is by this Art that all objects are truly represented just as they appear to the Eye be they ever so complex, and none of the Imitative Arts are capable of perfection but this; because it is the only one that is wholly within the sphere of Mathematical Science.
All objects deminish as they recede from the Eye and finally lose themselves in a point in the Horizon, called the point of sight; this point is always opposite to the spectator and on a level with his Eye; but as example is always better than precept, I herewith send to you a Drawing of a pavement with eight square Pillars set in two rows and at equal distances from each other, with the process of drawing them explained by the dotted lines.
I am / Sir / Your Most Obt: / Humbl: Sert.
John Singleton Copley