(874) 
Vublici Juris fecimus elapfo anno 165$. libellmn qumdam , cut tltulus] 
Sexaginta Problemata Gcometrica : In hujus cake Appendiculam adjunxi- 
mus , in qua occurritur Mario Bctti no , Cavaleriana Indivipbdia veluti 
D&monas pavent i. Vaucls vero tranfaftis diebus a modo ditti Libelli imprejfi- 
one . incidimus forte Venetiis in opfis Aureum And. liquet, CYL1N- 
D R I C A C^ANNULARIA nmcupAtum \ in quo cum incideremus tn 
Schol prop, 1 2. /. i, Authorcm carpere Indivifibilia invenimus. 
Boluimus vehement er (faith Angeli J Opus t ant a eruditione refertum non 
prius admanus noftras pervenijfe - 9 c en fur a autem in ipfo contra Indivifibilia 
pronnnciata , par urn aut nihil nosturbat : Vetera enim confine t & non nip e$- 
rummodica, & imbecilliora , qua priusab ipfo Cavalerio inVrdfat. Geome- 
tric Indivifibilium , & a Guldino in Centro-baryca objiciuntur ± quibus fatis 
fuperque occurrit ipfe Ca Valerius. 
And Angeli in the Preface of his Treatife De Infinitorum Spiratium Spati- 
orum Menfura (Venetiis 1660.) having occafion to mention thefruitlefs 
endeavour of Guldin in finding the Center of Gravity of a Spiral Line , 
and a Right line equal thereto , faith thus - 3 
P, Guldinus, Centrobarycd (Anno 1640. edit*) Author fdmo- 
fus (at Cavalerianorum Indivifibilium contemptor'& irrifor , quidumjndi- 
vifibilibus irrifit , feipfum ridiculum prdbuii) altius emnibus volatum fump- 
ftt, at conatu irrito, & Icari fine , ut ipfemetfatetur. 
But Guldinus doth not confefs himjfelf in an error in oppofing Cavaliers 
Geometria Indlvifibilittm , publifht 1632; but faith , he was very aged , of 
an infirme memory 5 and that he had not (as we may gather) leifure to per- 
tife it throughly i when be had health , nor health when he had leifure. 
The Controverlie , and the Reply about it , is exceeding pleafant , and to 
be found with other confiderable Mifcellanies in the Geometr. Exercitat. 
of Cavalerim printed at Boncnia 1647. Which Book if Tacquet hadfeen 
( for he quotes it not ) he would probably not have made any fuch oppo- 
sition. 
Angeli doth not only anfwer what is objected by Tacquet f butfhews, 
what famous Authors he hath on his fide , who have derived many excel- 
lent Inventions from this Method of Indivifibles , viz. Beaugrand y Rocca y 
Magiottus , Van Schcten , Rich, white, Bullialdus, Tcrricellius , whQ 
calls Cavalier 's Firft Book the Ocean of Indivifibles , and the Fountain of In- 
ventions. Of which Doctrine he renders many excellent Examples. 
Moreover the fame Angeli in the Preface to his fa iti Tract, De Infinit. 
Spiral. Spatiorum Menfura , hath thefe words : 
Vro Indivifibilibus efi Veritas if fa , ft ant que iHi omnes pr*clariji [mi Geome- 
try , quosin Epift. ad Lectorem Operisnoftri De Inflnitis Parabolis recenfui- 
mus quibus nuper ultro fe affociavh Vine. Viviani 1. 1. De Maximis & Mi- 
nimis , monito poft Prop. 1 7. ubi ait , Vt hoc loco , ex adverfo indirect a An- 
tiquorumvU per dupli 'tern poptionem , luce clarius pal eat 3 quantum facilita- 
tes, brevitatis , at que evident it nancifcatur enova direclaque methodo (refte 
tamen 
