This lens is employed in articles found in tourist resorts as a magnifying glass for miniature photographs of the locality.
By introducing a dispersive lens of flint the magnifying glass could be corrected for both chromatic and spherical aberrations.
This angle, therefore, divided by the magnifying power of the telescope gives the real angular distance of the centres of a double star.
If the ordinary convex lens be employed as magnifying glass, great aberrations occur even in medium magnifications.
In experiments with magnifying glasses, and through spars, the ordinary effects of magnifying and of alteration of view are sometimes produced; sometimes they are not.
Hence one of the best methods of determining the magnifying power of a telescope to measure the diameter of the emergent pencil of rays, after the FIG.
It is transparent, as I said before; and being laid upon the printed page, I have sometimes pleased myself with fancying it exerted a magnifying influence.
Hence a wide beam demands treatment with further apparatus (usually a telescope) of high magnifying power.
In magnifying glasses for direct vision the eye must always be considered.
A rumour of the new invention, which reached Venice in June 1609, sufficed to set Galileo on the track; and after one night's profound meditation on the principles of refraction, he succeeded in producing a telescope of threefold magnifying power.