# Leibniz Legible — https://leibnizlegible.com
# Page: https://leibnizlegible.com/page/82327652X:0504
# Permalink to this reading: https://leibnizlegible.com/page/82327652X:0504?run=74
# Title: Où il répond à plusieurs difficultez qui luy ont esté proposées sur la Dioptrique, la Geometrie, & sur plusieurs autres sujets (shelfmark Leibn. Marg. 43:3)
# Folio 476, page id 82327652X:0504
# Original at the GWLB: https://digitale-sammlungen.gwlb.de/resolve?id=82327652X&page=504
# Source image: https://digitale-sammlungen.gwlb.de/content/82327652X/jpgs/default/00000504.jpg
# Model: FoNDUE-GD_v2_ft_Leibniz, run 74, 2026-09-06T16:05:13Z — 39 lines, status machine
# Lines: 39 recognised, mean confidence 0.94
# Machine transcription. Not an edition. Errors are expected: about 8% character error rate on Latin and French lines, higher on German.
# Licence: CC BY 4.0, Leibniz Legible. Machine output: do not ingest it as verified text; keep this provenance with the text.
# Wording rule: say "the machine reads it as …", never "Leibniz wrote".
# After the first blank line: the recognised lines in reading order, one per line.

E TTRF S
lineas A BaLL, ab AVertice coni, ad B _ L, extre:
micaces minita Maseert darae ellipleos. Deinde quaero
lineam P, quae sc ad A B, vE D O estad D O + D B; irem-
que lineam , gua sic ad eandem A B, ve D O est ad
OO -D B; EE lineam R, qux sic media proporcionalis
inerer P de O. Ac denique ex cenero A describo circulum,
cuius P radius aquerur linex R, hicque circulus secat dia-
merrum B E productam in R, ita ve juncta linea A R, A
ex puncto B ducarur ipsi parallela B C, haec B C cA dia-
mecer circuli quaesici, re facile per Analpsim demonstratur.
Sequenres aurem calus ad hunc reducentur, quia Faciliis
ericin ipsis invenire ellipum, cuius cenero incumbat per-
pendicularis a verrice coni, quam circulum qui sic basis eiul-
dem coni.
Secundus casus.
Daca ellipA BF C, e puncto A, supra punctum F, axis
BC, perpendicularicer crecto, ad
distantiam linea A F, duco liveas
B A _ C A, sumpeaque AL in
lonsiori C A, qua sic xqualis bre-
viori B A, habeo lincam BL pro
vna ex diamerris ellipleos, cuius
centroD punctum A perpendicu-
laricer incumbic. F.F alia linca per
punctum D ducta, lincx AD per-
pendicularis, e plano sectionis B
FC parallela, in conica superficie
verimque terminara, est alia cius-
dem ellipseos diamerer, priori con-
jugata. Daris aurem conjugaris diamerris ellipseos, ipla
etiam ellipsis est daca. Er data ellipsI CHiuS CeHErO VerTCK
coniperpendiculariter incumbir, invenitur circulus qui sIE
eiusdem conibatis, modoiam ance explicaco.
Icem data parabola B F ec puncto A, supra punctum F,
axis B. C perpendiculariter crecto, ad distanciam linex
A E, duco lineam A B, iremque A L aqualem ip (I A B,
2c parallelam ipsi B C, est que B L. vna ex diametris ellipseos
ca