I have to thank you for the publication you have been pleased to send me, on the Cycloid, & it’s application to the diurnal rotation of the earth, to the winds & tides. it is a work of great Mathematical erudition; and it’s calculations & principles will doubtless excite the attention of Mathematicians of the first order. I propose to send two or three copies to my Mathematical friends beyond the water. but I feel myself undeserving the compliment you pay me in the invitation to pass a judgment on it’s merits. time was when I should have been delighted with such an investigation. but 40. years of abstraction, by duties of a different kind, from the higher mathematical studies, & from exercise in any, in fact, but those operations which the ordinary affairs of life occasionally call for, warn me against the presumption of pronouncing on the merits of such a work as this. when portions of it were not long since presented to the public in another form, I remarked them as coming from the hand of a master; & they in fact determined the choice of the mathematical preceptor for my grandson. I am much pleased to learn from you that he is pursuing his studies with profit. I have advised him, while with you, to devote himself almost exclusively to Mathematics. he can study Natural philosophy when alone, at leisure, & at home. I shall be delighted to see him attain a high degree of Mathematical knolege; because I know none so interesting & satisfactory. it gives us precision & certainty instead of the fancies & fables of other self-styled sciences. in these sentiments I recommend him to your kind attentions, which will be peculiarly gratifying to Sir