 | William Parsons (3rd earl of Rosse.) - 1844 - 78 pages
...its size to anneal. It is this three foot Speculum that is at present in the Telescope erected in Lis Lordship's lawn; the machinery of which will be described...sufficient for grinding. The several parts of the ma Si I V I chinery are connected by bands of leather in place of toothed wheels, which would be more... | |
 | Arts - 1844 - 498 pages
...It is this three foot speculum that is at present in the telescope erected in his lordship's lawn. It was not, however, chosen for this situation on...sufficient for grinding. The several parts of the machinery arc connected by bands of leather in place of toothed wheels, which would be more liable... | |
 | Elias Loomis - Astronomy - 1856 - 408 pages
...of fifteen parts of copper to seven of tin. The process of grinding was conducted under water, and the moving power employed was a steam engine of three horse power. The substance made use of to wear down the surface was emery and water, and it required six weeks to... | |
 | Thomas Dick - Philosophy and religion - 1869 - 664 pages
...penetrate into space depends. The process of grinding this speculum was conducted under water, and the moving power employed was a steam engine of three horse power. The substance made use of to wear down the surface was emery and water, a constant supply of these... | |
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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... 