VOL. VII.] PHILOSOPHICAL TRANSACTIONS. 13 



Diatriba, Numerisque Lunaribus ad novum Lunac Systema Horroccii. Lond. 

 An. 1(>72, in 4to. 



Mr. Horrox was also the author of that excellent tract, called Venus in Sole 

 visa, published by Hevelius, together with his Mercurius in Sole visus : who if 

 he had not been snatched away by an untimely death in the flower of his age, 

 would by his industry and exactness, which accompanied his great affection for 

 astrononjy, have very considerably advanced that science. Now we have only 

 left us these imperfect papers, digested with great care and labour, by that 

 learned mathematician Dr. John Wallis. 



III. Marcelli Malpighii Phil, et Medici Bononiensis Dissertatio Epistolica de 

 Formatione Pulli in Ovo : Lond. 16/2, in 4to. 



This exercitation of Signer Malpighi, contains an account of his having dis- 

 covered, that in fecund eggs, as well before as after incubation, the first rudi- 

 ments and lines of the principal parts of the chick are contained in the eggs; 

 whereas in subventaneous or addle eggs, inste^id of such a formation, there is 

 found nothing but an ^informed globous ash-coloured body, like a mola. Of 

 these prima stamina or beginnings, this author has traced the progress, by ob- 

 serving their changes, after incubation, every six hours, for the first two days ; 

 and after that, every 12 or 24, or 48 hours. In doing which, he has observed 

 many very curious and remarkable particulars, especially about the priority of 

 the motion of the heart before the production of true blood, though that liquor, 

 before it becomes red, be, according to him, before the motion of the heart; 

 as also about the said liquor first emerging, viz. whether it be a simple colliqua- 

 mentum, or a liquor vitalis, or a sanguis inchoatus : concerning which he 

 asserts, that the carina, and the beginnings of the head, brain, and spinal 

 marrow, do manifestly appear before the collection of that liquor, and its mo- 

 tion, and change into the nature of blood. 



IV. De Mente Humana Libri quatuor, &c. Auth. J. B. du Hamel P. S. L» 

 Par. An. 1672, in 12mo. 



The learned author of this book here treats of the nature, powers, functions, 

 and immortality of the soul. 



Mr. Isaac Neivtons Ansiver to some Considerations on his Doctrine of Light and 

 Colours : as printed in Number 80 oj^ these Tracts. N° 88, p. 5084. 



At the perusal of the considerations you sent me, on my letter concerning 

 refractions and colours, I found notliing that, as I conceived, might not without 

 difficulty be answered. And though I find the considerer somewhat more con- 



