(746) 
He hath alfo given a method of demonftrating the Sefiions 
of the Conic furfaces tbat have forbafe Parabolas, Ellipfes 
and Hyperbola's ; as alfothofeof Cylindrical rurfaces,which 
haveforbafe the fame Curves as well as the Circle* Of the Ufe- 
fulnefs of all which he believes every one that is knowing in 
Geometry is fufficiently perfwaded. 
Since the publication hereof, this fame Author hath printed 
h Latw aftieec, with elegant Schemes belonging thereto , Df 
Cycloide i;^ SeHionibus Comeu ; wherein hepromifesa continua- 
tion of this dodlrine 5 which, together with what is already 
extant, weexpefl: wholly in Latin, and it is the more defirable , 
becaufe we find him affirming, that he hath ftudied the Iviathe- 
aiaticks,and efpeciallythis part of them^for many years* 
III. Oj^khalmo^raphk , five , Oculi ejufque fartium Defcripth 
AmtomkA. Autb. Guil.Briggs ji,M. & Coll, Corp. Chrijli in 
AuL Cantabr. iiiJW. Cantabrigiae 1676. 120* 
T His Author having premifed fome general Confiderations 
touching the Eye, and therein given an account^ amoRgft. 
other particulars^ of the reafon why there is made but one fen- 
fation by both Eyes, and why fometimes the objed appears to 
be double \ defcends to the examination of the parts of that 
organ; and firft, to the iM«/5:/<fi , and their Ufes; Then to the 
CoiiU^ where he Gonfiders, why X\\e Uvea ov Choroides is black 
in Men, but of divers colours in Brutes $ why the Northern 
Nations have generally grey , but thofe of the Torrid zone, 
black eyes ; and why the Iru^ proceeding from the Uvea^ is of 
fo variegated a colour in fome Individuals; concerning which 
latter he is of opinion, that that comes from the extream fine 
texture of the filaments of the/m, by way of undulation dif- 
pofing the lucid matter , from a different reflexion , into fuch 
colour?. Further, when he difcourfes of the f^upilla , and its 
contraftion and dilatation, together with the caufe of that mo- 
tion^ hefuggefts,that,becauf€ the pupil cannot be duly dilated, 
whilft we lift up our eyes, and confequently not admit fomany 
rays as otherwife, the Stars do appear lefs about the Meridian^. 
iJian in the Horison» Again^ when he examines the Ketim^ he 
takesnotice, that that coat is made up of medullar fibres, be- 
twixt which and the brain there intercedes a very great commu* 
Tii cation ; upon which account he holds it to be the principal 
» organ 
