A Treatise on the Construction of Maps: Comprehending an Inquiry Into the Principles of Mathematical Geography and the Relations of Geography to Astronomy: with Rules for the Formation of Map-projectionsLongman, Green, Longman, Roberts, & Green, 1864 - 156 من الصفحات |
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altitude antarctic circles appear ascer ascertained assumed Astronomy axis bodies central meridian centre circumference comprised cone conical projection construction of maps corresponding cosine course degree of latitude degrees of longitude describe a circle diagonal scale diameter direction distance diurnal motion divided divisions east eclipses English miles equal equator extent extreme fixed stars gnomonic projection Greenwich heavens hemisphere horizon hour intersection length line A B London measure middle parallel moon motion north and south north pole number of degrees oblique observed occupy orbit parallels and meridians parallels of latitude passing perpendicular plane of projection point of projection polar circles pole of projection portion position primitive circle proportion quadrant radius represent the meridians right angles round the earth secant semi-tangent side south point south pole space sphere stereographic projection straight lines drawn supposed Table tangent tion Tropic of Capricorn tropics Uranus west points
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الصفحة 51 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
الصفحة 24 - ... one of which periods happened about 200,000 years ago — the earth in aphelion was nearly 98,500,000 miles distant, whilst now when in aphelion it is about 90,000,000 miles from the sun. . One result of the eccentricity of the orbit, combined with the obliquity of the ecliptic, or the angle that the axis of the earth makes with the plane of its orbit, is, that at present the sun is north of the equator about 7^ days longer than it is south of it. But as at the time the sun is south of the equator...
الصفحة 89 - A, it follows that (pr), or the height of the pole above the horizon is equal to the latitude of the place.
الصفحة 76 - ... and at a distance from the surface of the sphere equal to the sine of 45° of one of its great circles.
الصفحة 104 - ... find the number of miles which a degree of longitude contains, in the latitude of 39 degrees, vis.
الصفحة 61 - ... passes under this circle. It serves, therefore, as a general meridian, and is so called. The degrees of latitude, and even, on large globes, the minutes and seconds, are marked on the general meridian. The bearers, or feet of the whole machine, support a circular band of metal or wood ; it cuts...
الصفحة 55 - Assuming, then, that it is an ellipse, the geometrical properties of that curve enable us to assign the proportion between the lengths of its axes which shall correspond to any proposed rate of variation in its curvature, as well as to fix upon their absolute lengths, corresponding to any assigned length of the degree in a given latitude. Without troubling the reader with the investigation, (which may be found in any work on the conic sections,) it will be sufficient to state that the lengths which...
الصفحة 108 - AB, of indefinite length; bisect it in E, and at that point erect a perpendicular, ED, to form the central meridian of the map. Take a space for 5° of latitude, and, since Europe lies between the 35th and 75th parallels of latitude, mark off eight of these spaces along ED for the points through which the parallels must pass. The centre from which to describe the parallels will be the point in ED, where the top of a cone, cutting the globe at the 45th and 65th parallels, would meet the axis of the...
الصفحة 100 - Investigation of the conditions under which a spherical surface can be projected on a plane, so that the representation of any small portion of the surface shall be similar in form to the original;" this is, of course, merely the fundamental proposition of all orthomorphic projections.
الصفحة 24 - It is, therefore, in the equinox; and in this position the poles P, Q, both fall on the extreme confines of the enlightened side. In this position, therefore, it is day over half the northern and half the southern hemisphere at once ; and as the earth revolves on its axis, every point of its surface describes half its diurnal course in light, and half in darkness ; in other words, the duration of day and night is here equal over the whole globe : hence the term equinox. The same holds good at the...