VOL. I.J PHILOSOPHICAL TRANSACTIONS. 41 



A farther Account of an Observation on white Blood, 

 The substance of this paper is incorporated with a former account at p. 37. 



Of M. de Sons' Progress in working Parabolic Glasses. N" 7> p- 119. 



Since what was mentioned in a former paper respecting M. de Sons' noble 

 attempt to grind glasses of a parabolic figure, the publisher of these papers has 

 himself seen two eye-glasses of that shape, about one inch and a half deep, and 

 one inch and a quarter broad, wrought by this eminent artist with a rare steel 

 instrument of his own contrivance and workmanship, and by himself also 

 polished to admiration. And certainly it will be wondered at by those who 

 shall see these glasses, how they could be truly wrought to such a figure with 

 such a cavity ; and yet more, when they shall hear that the author undertakes 

 to excavate other such eye-glasses to above two inches, and object-glasses of 

 five inches diameter. He has likewise already begun his object-glasses for the 

 abovd-mentioned two ocular ones, of the same figure, of about two inches 

 diameter, which are to be left all open, yet without causing any colours. 



M. Auzout's Speculations on the Changes lihely to be discovered in the 

 Earth and Moon, by their respective Inhabitants, N° 7i p- 120. 



I have, says he, sometimes thought on the changes which it is likely the 

 supposed inhabitants of the moon might discover in our earth, to see whether 

 reciprocally I could observe any such in the moon. For example, that the earth 

 would appear to the people of the moon to have a different face in the several 

 seasons of the year ; and to have another appearance in winter, when there is 

 scarcely any thing green on a very great part of the earth ; when there are 

 countries all covered with snow, others all covered with water, others all ob- 

 scured with clouds, and that for many weeks together. Another face in spring, 

 when the forests and fields are green. Another in summer, when all are yel- 

 low, &c. Methinks such changes are considerable enough, by the force of the 

 reflections of light, to be observed, since so many differences of lights are seen 

 in the moon. We have rivers considerable enough to be seen, and they enter 

 far enough into the land, and have a breadth suflicient to be observed. There 

 are fluxes in certain places, that reach into large countries, capable of making 

 there some apparent change ; and in some of our seas there float sometimes 



amounting to 22 volumes in folio, 1 1 in quarto, and 3 in octavo. Most of them indeed are rather 

 curious than useful; many of tliem visionary and fanciful j and it is not to be wondered at, if they 

 are not always accompanied with much exactness or precision. 

 VOL. I. F 



