Johnson's natural philosophy and key to philosophical charts : illustrated with 500 cuts; being reduced photographic copies of all the diagrams contained in the author's philosophical series of indestructible school charts ; for the use of schools and families (1878)
N, is on the axis at apoint in the circle of which the convex surface of the lens forms a part.Hence, the principal focal distance is equal to twice the radius of thecurvature, as represented in tlie diagram. ^09. Figure 36.—Conjugate Foci.—These are any two pointson the axis of a lens, so situated… … parallel rays. If the radiant, L, be situated beyond the principalfocus, as it is, the diverging rays will be brought to a point at the eye,somewhere beyond the principal focus on the right. These two points,L and the eye, are conjugate foci; and it matters not upon which sideof the lens the…
Physics · Astronomy
Internet Archive · University of Connecticut Library · Public Domain Mark 1.0. Free to use for anything.
