$54 PHILOSOPHICAL TRANSACTIOxVS. [aNNO I676. 



contacts, or by other tangents : which he says comprehends a great part of the 

 propositions of Apollonius; and many others also of which he has not spoken : 

 which seems to him very easy to understand, forasmuch as it is nothing else but 

 a continual repetition of the application of one only line cut in three parts, which 

 line he calls cut harmonically; not that the parts taken separately are in harmo- 

 nical proportion, but that, by taking one of the extremes for one, and the 

 same with that of the middle for another, and the whole for the last, these 

 three lines should be in harmonical proportion. 



After he had dispatched this proposition, he says that he was resolved to have 

 concluded his book with the properties and relations of the ordinates to the rect- 

 angles of the parts of their diameters; but that he found himself insensibly 

 engaged to add to it some other propositions of a more useful kind, and which 

 might easily be demonstrated by the first; and then, the propositions of the 

 ancients about the foci or puncta comparationis; and the demonstrations by 

 him given of them he affirms to be different from those of others^ that so this 

 work of his might not only be entire, but new. 



He has also given a method of demonstrating the sections of the conic sur- 

 faces that have for base parabolas, ellipses and hyperbolas ; as also those of 

 cylindrical surfaces, which have for base the same curves as well as the circle. 



III. Ophthalmographia, sive, Oculi ejusque partium Descriptio Anatomica. 

 Auth. Guil. Briggs, A. M.et Coll. Corp. Christi in Acad. Cantabr. Socio. Can- 

 tab. 167^, in 12mo. 



A good description of the eye, accompanied with observations on vision. 



A Declaration of the Council of the Royal Society, passed Nov. 20, l676i 

 relating to some passages in a late book of Mr. Hooke, entitled Lampas, &c. 



Whereas the Publisher of the Philosophical Transactions, has made complaint 

 to the Council of the Royal Society, of some passages in a late book of Mr. 

 Hooke, entitled Lampas, &c. and printed by the Printer of the said Society, 

 reflecting on the integrity and faithfulness of the said Publisher in his manage- 

 ment of the intelligence of the said society : this council has thought fit to 

 declare in the behalf of the publisher aforesaid, that they knew nothing of the 

 publication of the said book; and further, that the said publisher has carried 

 himself faithfully and honestly in the management of the intelligence of the 

 Royal Society, and given no just cause of such reflections. 



The Council having thus justified the publisher, he shall only add that part of 

 a letter, written to him by M. Huygens, the 20th of Feb. 1675, which relates 

 to the taking out a patent of his, the said M. Huygens's invention; and then let 

 the world judge of the postscriber's accusation, about an endeavour to defraud 

 him of his contrivance. The words of the said letter, Englished, are these: 



