VOL. VII.] PHILOSOPHICAL TRANSACTIONS. 743 



in the posterior face of the prism; as is easily shown. Then from that given 

 length of the image, and its distance from the indivisible hole, as also from the 

 position and form of the prism, and besides from the inclination of the incident 

 rays, and from the angle which the refracted rays bending to the middle of the 

 image make with those that are incident from the sun's centre, all other things 

 may be determined. And the same data that determined the refractions and 

 positions of the rays, arc sufficient for an accurate calculation of these refrac- 

 tions. But this matter seems not to be of importance enough to be much re- 

 garded. 



As to the Rev. Father's calling our doctrine an hypothesis, I believe it only 

 proceeded from his using the word which first occurred to him, as a practice has 

 arisen of calling by the name hypothesis whatever is explained in philosophy; 

 and the reason of my making exception to the word, was to prevent the preva- 

 lence of a term, which might be prejudicial to true philosophy. 



The above answer being sent to the Rev. Father Ig. Pardies, he returned his 

 acknowledgment in a note as below. 



I am quite satisfied with Mr. Newton's new answer to me. The last scniple 

 which I had, about the Experimentum Crucis, is fully removed. And I now 

 clearly perceive by his figure what I did not before understand. When the ex- 

 periment was performed after his manner, every thing succeeded, and I have 

 nothing further to desire. 



An Account of some Boohs. iV** 85, p. 5019* 



I. Scarborough Spa Spagyrically Anatomized, An. 167O; And a New Yearns 

 Gift for Dr. Witty; London, 1671 ; both in l2mo. by George Tonstal, M.D. 



To particularise the contents of these tracts, would be an abuse of the 

 reader's time and attention. 



II. New England's Rarities discovered ; together with the remedies used by the 

 Natives to cure their diseases, wounds, and sores, &c. by John Josselin, Gent. 

 London, 1672, in 12mo. 



Later and more accurate accounts of the natural productions of North Ame- 

 rica, and of the diseases of that climate, render it unnecessary to notice the 

 contents of this book. 



III. A Rational way of preparing Animals, Vegetables, and Minerals, for a 

 Physical use: by Edw. Bolnest, Med. Reg. Ord. London, ^Qjl^ in 12mo.. 



A book of no use to the modern student, or practitioner of Physic. 



IV. Miscellanea Curiosa Physico-Medica Academiae Naturae Curiosorumt 

 annus secundus. Jense 1671, in 4to, 



