Some ConfiderAtlm 
0f MrMk. Mcrcator , concerning theGeomitric^/Mdi Mreft Method ef 
Signior Caflini for finding the apogees, ExcentricitieSy and j^nomalies 
ef the Planets; as that veas printed in the Journal des Scavanso/ Scp- 
tcmb.2. 1669; which Confiderations are here delivered in theLmnc 
T ongue, wherein they ^ere written hj the Atithor , as chiefy regardi»i 
theXeartt*din AflroKomj y yii. 
Clarijpmi Caflini Methodm 
Invefiigandi ^pogia, Ex centric it at es & Anom^Uas Planetarumy he^ 
viter Expoftta & Demsnfirata* 
SUpponit CI. CaJpntiSy^i Planctam in Eflipfi movcntem extendi ab utro- 
que focoduasrcdas, quarum altera fit wfrfw,altcra auteniT'rrjmotus 
linca. Conftruftio porro talis eft 5 
Fig, IL L eft Centrnm Coneentrici 
ABCDE. 
BLDeft Diameter. 
B A, B C, B P, funt intervalla appa- 
remi^i. 
D.E, D F, D funt intervalla me- 
diorum motuiim. 
BE,BF,BCL; itemDA,DC,DP, 
fvint linear redac. 
B E fecat D A in H ; fecat DC in 
G-,BQ.fecatDPinR. 
RHGeftiinea refta. 
B I eft perpendicularis ad R H G. 
I eft Centrum Ellipfeos. 
LI eft Excentricitas, 
lO=:Ll. 
O eft focus , circa qiiem ordinatur 
medins rnotus ; circa quern 
verus. 
IM = IN — LB, 
M eft Apogeon ^ N,Perigeo,n» ELM 
Anoraalia vera. 
*Demonflratio. 
/. Illuftriflimus ac Reverendiff, «y^-fi^/v/ irW^r/ , quondam in Celebefr. 
Acad, Oxm. ProfcfTor Aftronomiae Savilianu»^ nunc Epifcopus Sarisburien- 
fis, in Examine AFironomiA Philolaica^ cdito Oxon. A. 1 5 J ? . c. 6. docuit 
Methodum , cx data Anomalia media Pianetarum ^ inveftigandi veram j 
quae eft hujufmodi ! 
Fig, III. C, eft Centrum Ellipfeos AEP ; F, focus,cir€a quern ordina- 
tur medius motus. S, focus, circa quem ordinatur verus mocus. A , Apo- 
geon. P,Perigeon, E,Erro fivePlaneta. AFE, Anomalia media. ASE, 
Anomalia vera . FET, linea reSa, E T = S E, S T eft linea refta. 
JnAo SFTdantur, i. S F diftantia focorum t 2.FT = FE + ES 
ZZ^^' 5. A FT, angulus externus, five Anomalia raedii , squalls fum- 
nx angulorum F ST & T. Ergo inveniri poteft FS E, five Anomalia ve- 
ra, acqualis differentia Angulorum FST & T, Nimirum 
VC 
