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angle appearance Astronomer Royal atmosphere bright calculated changes character circle colour Comet communication compared comparison complete considerable contains corrected course dark Declination Delaunay determined diameter direction disappearance disk distance ditto drawings Earth Eclipse edge effect Equatoreal error existence extending give given Greenwich important inches increase interesting July latitude length less letter light limb longitude lunar magnitude Mars Mean Mean Solar measures Memoir mentioned Monthly Notices Moon Moon's motion nearly object observations Observatory obtained Occultation occurred Parallax period Plana planet portion position present probable Prof Professor rays recorded reference refraction remarkable respect ring Satellites seen side Sirius Society Solar spots stars Sun's surface taken telescope terme theory tion visible whole
Page 130 - Arranged to meet the requirements of the Syllabus of the Science and Art Department of the Committee of Council on Education, South Kensington.
Page 46 - ... next, giving an alloy of excellent quality. The ordinary coppers of commerce generally fail, owing, it is said, to the presence of iron, which appears to be specially prejudicial. Further, the alloy must be melted two or three times, as that obtained from the first melting is excessively brittle. " Each successive melting, up to a certain point determined by the working, and particularly the forging properties of the metal, improves its tenacity and strength.
Page 45 - Its hardness and comparative inoxidizability point it out as peculiarly adapted for pivots, axes, and bearings. If employed for receiving the graduation of circles, the necessity for inlaying another metal will be obviated, by which two advantages will be gained ; the hammering which forms part of the operation of inlaying, and which, more or less, must cause unequal density and tension in the circle subjected to such treatment, will be dispensed with ; and the effect of inequality of expansion in...
Page 18 - One is reminded, in this connection, of the remark of Pond, that "we can hardly obtain a better test of our power of predicting the future positions of stars than by trying by the same formula, how accurately we can interpolate for the past. In a variety of papers which I have submitted to the Royal Society, I have endeavored to show, that, with us, the experiment entirely fails.
Page 45 - ... is far superior, not in one or some, but in every respect, to any metal hitherto used for the construction of philosophical apparatus, and that for such purposes it may be employed in the dimensions that would be proper in the case of cast steel. All parts which would otherwise be made of steel may with perfect safety, and even with advantage, be made of the new alloy, particularly such parts as bolts, and fixing, tangent, and micrometer screws. Its hardness and comparative inoxydizability point...
Page 18 - ... this happens the motion is always southward. I have yet met with no exception to this rule: not a single star can be found having an extra tendency to northern motion ; and, indeed, the northern motion in any star is so very small that it would never have excited attention. " A very great deviation will be found in three very bright stars, Cape'lla, Procyon; and Sirius ; the proper motion of each of these is southward : it therefore follows that these proper motions are accelerated.
Page 86 - A prolongation of very faint light stretched on either side from the dark shade on the ball, overlapping the fine line of light formed by the edge of the ring, to the extent of about one-third its length, and so as to give the impression that it was the dusky ring, very much thicker than the bright rings, and seen edgewise, projected on the sky.
Page 153 - Minister on the nomination of the Secretary of State for War, the Secretary of State for India and the First Lord of the Admiralty.
Page 179 - Stars," as an earnest of the results of twelve months' observations of some 30 or 40 stars, the Moon, Jupiter, and Mars, which are to follow. The valuable observations of Dr. Miller on the photographic spectra of the metals, &c., are too well known to require mention here, did not a recent deduction from them hold out great promise of doing for the temperature of the...
Page 45 - ... operation of inlaying, and which, more or less, must cause unequal density and tension in the circle subjected to such treatment, will be dispensed with ; and the effect of inequality of expansion in the circle and the inlaid strip will no longer be a cause of apprehension. With respect to the due visibility of divisions cut on this metal, opinions will perhaps differ. I can only say that I should be well content to observe with them.