Geometry: Tangent Circles and Groups of Crossing Lines
Two internally tangent circles and zig-zag groups of intersecting straight lines, with a proposition reference
The leaf carries pen studies in plane geometry: at upper right two circles are drawn one inside the other and touching, and below them are two zig-zag groups of straight lines crossing one another. A brief heading cites the 'fifth [proposition] of the third [book],' a reference to a geometric authority. Fainter figures and annotations appear elsewhere on the sheet, partly show-through from the reverse, so further untranscribed marks are present.
On this page
Two circles internally tangent to one another
A caption identifies a pair of circles drawn so that one lies inside the other and the two touch at a single point. The small figure sits at the upper right of the page.
Two groups of intersecting lines
A second caption labels two clusters of straight lines that cross one another, drawn as two bold zig-zag figures. They are studies of how sets of lines intersect within a plane.
Citation of the fifth proposition of the third book
A short heading names the 'fifth [proposition] of the third [book],' pointing the diagrams to a numbered theorem in a geometric treatise. It marks the studies as demonstrations of an established result.