Ter Circles, thediftances of the Poiats of interfeftioaare the 
Tangents of the half and the whok Arch of the Mferidimfoin- 
teifefted. But as to the Points of Interfedion , which determine 
the Problem propofed, they may be found without the aid of the 
former way, from a Gnoonmiekmi. Stereografhick method of mca- 
jfuring and fetting off the fides and angles of Spherical Triangles 
ill thofe Pro jeftions, which isneceffary in what follows. 
3 , Ir the Problem is to be perform'd by Mixt Gemetrj , as by 
a Circle and cither a p^r^j^^/^ , Hyper hU^ or E Hip fis ^ the Ov" 
cle may be conceived to be the Su3-coatrary Sedion of a Cons 
projeftedby the Eyatthe South-foU, and any of the reft of the 
Seftionsby the Ey at the Center of the Sphere. 
4. If by any of the Coffick Sections however pofited 5 thcpro- 
jeiiing Plain may remain the fame, but the Eye muft be in 
fome other part of the Surface of the Sphcre,and not in the Axis. 
Thefe things were mentioned to invite the Learned 
to their Confideration : I (hall only further adde , that we can- 
not {ay,what may be expcifted from the labours and endea- 
vors of divers Learned men of this Nation , particularly from 
Dr. WaSis , who hath fo excellently refolved and conftrudled 
all Cubick ^quAtigns at the end of the firft Treatifeof his epe- 
ra Jdathematica by aide of a Cubick ParahoU(ler ^ mentioning, 
thatby fuch Curves the Roots of all iEquations may be found: 
And who hath promifeda Trcatife o{ Algebra, and AngttUr Se{Ii^ 
ens^ wherein the Reader need not doubt to meet with facisfadion 
in thefe Myfteries.Nor ought we to omit the mentioning of the 
Modeft and Learned }Ar. Barrow, wbo(araong many other ex- 
cellent Subjedis, and particularly his Opticks now, at the Prefs) 
hath perform'd,what the famous Italian Geometer Mich. A^ Ricci 
hathpromird mBxercitat, Geometrica f printed at Rome 1666. 
and lately reprinted here) about C/^ri/^/ of feveral degrees* that 
lerve to determine and refolve all tyEquations : which hath like*» 
wife been done by other Leirn'd men of this Nation. 
c; An AccBunt of 'Books. 
I, PR^LUDI A BOT ANICARobertiMorifon 
' Scoti Ahrdonerifis.Lon ^if^^. impQaCis^ac^ AlleHr%i66^, inS^. 
This Prelude of this S^cellent Botanift hath two parts 5 The 
firft gives us an Alphabecical Catalogue of all the Planes in the 
