VOL. VI.] PHILOSOPHICAL TRANSACTIONS. 6ll 



For as we now know that there are stars which appear and disappear from time 

 to time, so we have cause to suspect, that most of the stars that were not seen 

 formerly, or that are seen no more now, or are found diminished, are of the 

 same nature with the star in the Whale's neck, and do not cease to be in tlie 

 heavens, though they there appear not. 



It is also possible, that these new stars not only were in the heavens, but 

 even appeared there before they were taken notice of as new ones : And it is 

 very probable that it is also with most stars, as with that in the neck of the 

 Whale, which was not observed at first, but when it was already of the third 

 magnitude ; although it has been since found, that it is not really so great when 

 it begins to appear, but that being very small in the beginning, it increases in- 

 sensibly until it come to that magnitude.* 



An Answer of Dr. Wallis to Mr. Hobbes's Rosetwn Geomefricum, in 

 a Letter to a Friend in London, dated July 16, I67I. N" 73, 

 p. 2202. 



Further refutations of Mr. Hobbes's pretended quadrature of the circle, and 

 other geometrical errors; now of no use, and not even to be read without the 

 books themselves, from whence the quotations are made. 



An Account of some Boohs. N° 73, p. 2210. 



I. De Motionibus a Gravitate Dependentibus Liber Job. Alphonsi Borelli, 

 in Academ. Pisana Matheseos Professoris : Regio Julio, 1670, in 4to. 



The learned author of this book maintains, that all sublunary bodies have 

 gravity : that they exercise this in endeavours to approach towards the centre 

 of the earth : that the superior body, or the superior parts of the same solid or 

 fluid, gravitate on the inferior, when at rest : that there is no positive levity in 

 nature: that lighter bodies ascend, because thrust out of their place by heavier: 

 that the air is heavy, elastic or springy, and thereby performs those things that 

 were wont to be ascribed to fuga vacui ; that the same is capable of very great 

 expansion and contraction : that there is not in nature any proper attraction or 

 suction; but things seeming so to be performed, are done by the pulsion or 

 trusion of other bodies : that there is a necessity and a great use of vacuities in 

 nature, notwithstanding the subtle and all-pervading matter of Descartes; with 

 many other things consonant hereto. For these assertions he brings argu- 

 ments; answers objections and difficulties, and particularly those that are 



* In the future volumes of this work, we shall find many other notices of changes in the stars, 

 and even a history of the new ones by Dr. Halley, in volumo 29 of the Philosophical TransactioiM. 



4 H 2 



