The eye which was thus brilliantly illumined looked through a lens of some power.

Of the four monads described and figured by these investigators, one, as I have said, very closely resembles Heteromita lens in every particular, except that it has a separately distinguishable central particle or "nucleus," which is not certainly to be made out in Heteromita lens; and that nothing is said by Messrs. Dallinger and Drysdale of the existence of a contractile vacuole in this monad, though they describe it in another.

For some little time after this the Earth was entirely invisible; but later, looking through the telescope adjusted to the lens on that side, I discerned two very minute and bright crescents, which, from their direction and position, were certainly those of the Earth and Moon, indeed could hardly be anything else.

" He handed the two photographs up to the judge, together with the 'Thumbograph,' the memorandum slip, and a powerful doublet lens with which to examine them.

In truth, I should say that the various disadvantages due to the atmosphere deprive the astronomer of at least one-half of the available light-collecting power of his telescope, and consequently of the defining power of the eye-piece; that with a 200 glass he sees less than a power of 100 reveals to an eye situated in space; though, from the nature of the lens through which I looked, I cannot speak with certainty upon this point.

Then he pulled over me a great movable lens as of a microscope, which concentrated the insupportable light.

I found him looking through a lens at some epilichnions with the earth still adhering to them, he had received from the Peloponnesus.

The subject of distortion was next treated of, and the manner in which the idea of a non distorting doublet could be evolved from a single bi-convex lens by division into two plano-convex lenses with a central diaphragm was shown.

The latter defect was corrected by altering the angles, and then astigmatism was corrected by a cylindrical lens near the slit.

As each picture, showing some particular motion, is taken, the film halts for the briefest space of time, and then goes on, to be wound up in the box, and a new portion brought before the lens for exposure.

The building exhibits almost every style of architecture, from the Norman work of William of Lens to the late Perpendicular of Prior Goldstone, and yet the work of composition and design has been so exquisitely carried out that there is no hint of any want of harmony in the magnificent whole.

During the battle of Lens up to this time (from August 15 to 22) the Canadians took 1,378 prisoners, 34 machine guns and 21 trench mortars.

[Illustration: Fig. 129.Diagram showing the Change in the Lens during Accommodation.