The Monster Telescopes, Erected by the Earl of Rosse, Parsonstown: With an Account of the Manufacture of the Specula, and Full Description of All the Machinery Connected with These Instruments

Front Cover
Shields, 1844 - Astronomical instruments - 54 pages
0 Reviews
Reviews aren't verified, but Google checks for and removes fake content when it's identified
 

What people are saying - Write a review

We haven't found any reviews in the usual places.

Other editions - View all

Common terms and phrases

Popular passages

Page 14 - It was not however, chosen for this situation on account of its superiority over the compound Speculum, as there could be scarcely any difference found to exist between them : there is, however, a slight diffraction of light, caused by the edges of the pieces of the latter, but it does not interfere to such a degree with its performance as to be taken into account. The processes of grinding and polishing were precisely similar in the case of each, and the machinery was the same. We premise that the...
Page 38 - E the eye-piece ; F the moveable pulley ; G the fixed one ; H the chain from the side of the tube ; I the chain from the beam ; K the counterpoise ; L the lever ; M the chain connecting it with the tube ; Z the chain which passes from the tube to the windlass over a pulley on a truss-beam which runs from W to the same situation on the opposite wall — the pulley is not seen.
Page 36 - ... built, 72 feet long, 48 high on the outer side, and 56 on the inner — the walls being 24 feet distant from each other, and lying exactly in the meridional line. When directed to the south, the tube may be lowered till it become almost horizontal ; but when pointed to the north, it only falls till it is parallel with the earth's axis, pointing then to the pole of the heavens. Its lateral movements take place only from wall to wall, and this commands a view for half an hour on each side of the...
Page 16 - This ball is connected with a lever acting upon some part of the machinery, which controls the power or regulates the amount of resistance, as already explained in the case of the governor. When the level of the water rises, the buoyancy of the ball causes it...
Page 35 - The diameter of the tube is 7 feet. It is fixed to mason-work in the ground, to a large universal hinge, which allows it to turn in all directions. At 12 feet distance on each side, a wall is built, 72 feet long, 48 high on the outer side, and 56 on the inner, the walls being 24 feet distant from each other, and lying exactly in the meridional line. When directed to the south, the tube may be...
Page 40 - F. with the horizon, and that it is required to elevate it, the windlass is turned, and the chain being shortened, the desired effect is produced; but the labour of this would be immense if the...
Page 49 - ... only encouraged those undertakings in others he would merit our praise; but when we see him, without losing sight of the duties of his station in society, give up so much time and expend so much money on those pursuits himself, and render not only his name illustrious but his rank...
Page 19 - When, however, the focal length neither increases nor diminishes, the abrasion will become uniform over the whole 20 surface producing a spherical figure. According, however, as the focal length (the actual average amount of abrasion during a given time being given) increases more or less rapidly, the nature of the curve will vary, and we might conceive it possible, having it in our power completely to control the rate at which the focal length increases, so to proportion the rate of that increase,...
Page 16 - ... surface; and KL the polisher, which is of cast-iron, and weighs (for a 36-inch speculum, to which also the other dimensions above specified correspond) about 2- cwt. ; M is a round disc of wood connected with the polisher by strings hooked to it in six places, each two-thirds of the radius from the centre. At M there is a swivel and hook, to which a rope is attached, connecting the disc with a lever and counterpoise weight, so adjusted as to sustain the whole weight of the polisher, all but...

Bibliographic information