Treasury of Optics

8. The center of the uvea sphere is lower than the centers of the remaining parts of the eye. 8 p 3.

An ornate decorative initial E begins the paragraph.
And because the concave surface of the cornea touches the surface of the humor albugineus aqueous humor which is in the anterior foramen of the uvea, and its interior surface and the convex surface of the humor albugineus are also a spherical surface whose center is the center of the surface superimposed upon it. Therefore, the manifest surface of the cornea and the interior surface of the uvea, and the line that passes through the center of the uvea and through the center of the cornea, are equidistant spherical surfaces. Their center is therefore one common point, and it is remoter in depth than the center of the uvea. The line that passes through the center of the uvea and through the center of the foramen that is in the anterior of the uvea, when it is extended straight, will pass through the middle of the concavity of the nerve upon which the eye is composed, because the foramen that is in the anterior of the uvea is opposite the foramen that is in the posterior part of the uvea, which is the extremity of the concavity of the nerve.

9. A straight line connecting the centers of the crystalline and uvea spheres, when extended, falls into the center of the circle conglutinating the crystalline and vitreous spheres with the uvea: and it is perpendicular to it. 10 p 3.

An ornate decorative initial E begins the paragraph.
The anterior surface of the glacialis crystalline lens is also a spherical surface, and it cuts the uvea sphere. Its center is therefore remoter in depth than the center of the uvea. The straight line that connects their centers passes through the center of the circle of intersection and is perpendicular to it. The circle of intersection between the surface of the anterior glacialis and the surface of the uvea sphere is either the circle defining the end of the consolidation between the glacialis and the uvea, or it is equidistant to it. Because the surface that is in the anterior of the glacialis is opposite the foramen that is in the anterior of the uvea, its position is similar to it. The end of this surface (which is the circle of intersection between the two surfaces of the glacialis and the uvea) is therefore either the circle of consolidation itself or equidistant to it. If the circle of intersection between the two surfaces of the glacialis is the circle of consolidation, this circle is the circle of intersection between the surface of the anterior glacialis and the surface of the uvea. And if the circle of intersection between the two surfaces of the glacialis is equidistant to the circle of consolidation of the glacialis sphere with the uvea (which indeed happens if the consolidation is in the posterior part of the glacialis), then the surface of the anterior part of the glacialis, when it is mentally extended over that which is from its sphere, will cut the uvea sphere upon a circle equidistant to this circle, namely the circle of intersection between the two surfaces of the glacialis due to the similarity of the position of this circle to the circumference of the uvea sphere. And because this circle is equidistant to the circle of consolidation, the circle of intersection between the surface of the anterior glacialis and the uvea sphere will be either the circle of consolidation itself or equidistant to it. If this circle is the circle of consolidation, the straight line that passes through the center of the anterior glacialis and through the center of the uvea will pass through the center of this circle and will be perpendicular to it, because this circle will be the circle of intersection between the two spherical surfaces. But if this circle is equidistant to the circle of consolidation and is equidistant to the circle of intersection between the two surfaces of the glacialis, it is therefore with the circle of intersection between the two surfaces of the glacialis on one spherical surface, which is the surface of the anterior glacialis, and it is equidistant to the circle of intersection. The line therefore that passes through the center of the uvea and through the center of the surface of the anterior glacialis passes through the center of the circle of consolidation according to all dispositions, and is perpendicular to it, whether the circle of consolidation is the circle of intersection between the surface of the anterior glacialis and the uvea sphere, or whether it is equidistant to this circle.

10. The center of the crystalline sphere is higher than the center of the vitreous sphere. 11 p 3.

An ornate decorative initial E begins the paragraph.
And again, the surface of the anterior glacialis and the surface of the remaining glacialis are two spherical surfaces intersecting one another. Therefore, the center of the anterior surface is remoter in depth than the center of the posterior surface.

11. A straight line connecting the centers of the spheres and the uvea, when extended, falls into the center of the vitreous [sphere] and the middle of the cavity of the optic nerve. 12 p 3.

An ornate decorative initial E begins the paragraph.
The straight line that connects these two centers passes through the center of the circle of intersection and is perpendicular to it. It has already been declared [note: see 9] that it passes through the center of the circle of consolidation and is perpendicular to it; however, this circle is either the circle of intersection or equidistant to it. The line therefore that passes through the center of the uvea, through the center of the anterior glacialis, and through the center of the circle of consolidation, and is perpendicular to this circle, passes through the center of the remainder of the glacialis. And when this line passes through the center of the remainder of the glacialis and through the center of the circle of consolidation, and is erected upon the circle of consolidation at right angles, it extends in the middle of the concavity of the nerve upon which the eye is composed, because the circle of consolidation is the extremity of the concavity of the nerve. And it has already been declared [note: see 7] that the line passing through the center of the uvea, the center of the cornea, and the center of the foramen that is in the exterior or anterior of the uvea, extends in the middle of the concavity of the nerve. Therefore, this line, which passes through the two centers of the surface of the glacialis and through the center of the uvea, is the very line that passes through the center of the cornea and through the center of the foramen that is in the anterior of the uvea. Therefore, this line passes through the center of the cornea, through the center of the uvea, through the two centers of the surface of the glacialis, through the center of the foramen that is in the anterior of the uvea, and through the center of the circle of consolidation, and passes through the two middles of all the membranes opposite the foramen of the uvea. It is perpendicular to the surfaces of all the membranes opposite the foramen of the uvea, is perpendicular to the surface of the foramen of the uvea, is perpendicular to the surface of the circle of consolidation, and extends in the middle of the concavity of the nerve upon which the eye is composed.