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They had to raise enormous stones, massive pieces of wrought iron, heavy corner-clamps and huge portions of cylinder, with an object-glass weighing nearly 30,000 pounds, above the line of perpetual snow for more than 10,000 feet in height, after crossing desert prairies, impenetrable forests, fearful rapids, far from all centers of population, and in the midst of savage regions, in which every detail of life becomes an almost insoluble problem.
In doing this we need not go through with the formation of the several membranes, humors, etc., but take the crystalline lens as the most curious and nicely arranged and adapted of all the parts, and as giving, moreover, a close parallel, in the end produced, to that produced by design, by a human designer, Dollond, in forming his achromatic object-glass.
Captain Lange smoking while under fire. Japanese shrapnels indicate the line of our trenches in the air. Then he put his note-book down beside him and crept under his kodak again, carefully fixing the object-glass on the battery opposite. Now then! A streak of solid lightning flashed in front of the second gun, and a black funnel of smoke shot up. Click! No. 847.
'In no way but by giving me your good wishes in what I am going to tell you on my own account. He spoke in tones of mysterious exultation. 'This parcel is going to make my fame! 'What is it? 'A huge object-glass for the great telescope I am so busy about! Such a magnificent aid to science has never entered this county before, you may depend.
This, in its turn, was surpassed by two of respectively 29-1/2 and 30 inches, sent by Gautier of Paris to Nice, and by Alvan Clark to Pulkowa; and an object-glass, three feet in diameter, was in 1886 successfully turned out by the latter firm for the Lick Observatory in California.
At one end there is the object-glass, and at the other end the eye-piece, and of course it is obvious that with an instrument of this construction it is to the lower end of the tube that the eye of the observer must be placed when the telescope is pointed to the skies.
It will never be right, although I have had it altered two or three times. When it was shut it caught the object-glass inside. I remedied that defect, but only to create a worse, for then the instrument shook about. So it is, when once a thing is badly done, you had better get rid of it; it is of no use to bother with it.
Airy combined the functions of both, and employed the same constructors as before to make a transit-circle with a telescope of eleven and a-half feet focus and a circle of six-feet diameter, the object-glass being eight inches in diameter. Airy, like Bradley, was impressed with the advantage of employing stars in the zenith for determining the fundamental constants of astronomy.
Cooke, of York, made an object-glass, 25-inch diameter, for Newall, of Gateshead, which has done splendid work at Cambridge. We have the Washington 26-inch by Clark, the Vienna 27-inch by Grubb, the Nice 29-1/2-inch by Gautier, the Pulkowa 30-inch by Clark.
The "slitless spectroscope" consists simply of a prism placed outside the object-glass of a telescope or the lens of a camera, whereby the radiance encompassing the eclipsed sun is separated into as many differently tinted rings as it contains different kinds of light. These tinted rings were simultaneously viewed by Respighi at Poodacottah, and by Lockyer at Baikul.
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