Iconographic Encyclopaedia of Science, Literature & Art, Volume 1

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Page 9 - The square described on the hypothenuse of a rightangled triangle is equal to the sum of the squares described on the other two sides.
Page 9 - ... to facilitate his progress in the scholastic instructions that may be afterwards imparted. His idea of length, measure, or distance, may be rendered somewhat definite, by presenting to him pieces of wood of the length of an inch, a foot, a yard, and a pole, and causing him to notice how many lengths of the one is contained in that of the other ; and the idea of the specific gravities of bodies may be impressed, by causing him to lift a weight of brass or cast iron, and another, of nearly the...
Page 13 - ... most compact and useful, perhaps, that has yet been invented. It consists of a number of concentric grooves, whose respective diameters are regulated by the quantity of cord which must pass over their peripheries in equal spaces of time. In this system and all others where a single cord is employed, the power is to the weight as .1 to the number of parts of the cord acting on the lower block, or as 1 to twice the number of pullies in the lower block, and as in the system shown by Fig. 24, the...
Page 20 - The spherical excess of any spherical polygon is equal to the excess of the sum of its angles over two right angles taken as many times as the polygon has sides, less two.
Page 8 - Each side about the right angle is a mean proportional between the whole hypotenuse and the adjacent segment.
Page 102 - From the earth outwards the seven first circles represent the paths of the following bodies as planets, and in the following order :•—the Moon ; Mercury ; Venus; the Sun ; Mars ; Jupiter; and Saturn. The eighth circle, e, represents the path of the fixed stars...
Page 68 - Hence a straight line drawn from the vertex of an isosceles triangle, to the middle of the base, is perpendicular to that base, and divides the vertical angle into two equal parts.
Page 25 - When a = b, it becomes y' = x1 — a1 ; such a hyperbola is called equivalent. The asymptotes of this form a right angle with each other. The parabola is produced when the plane of intersection is parallel to the side of the cone ; it also is an open curved line, but has only one focus. Every point of the curve is equally distant from the focus and a fixed straight line called the directrix. It also consists of two symmetrical, infinitely extending branches, which unite in a point half way between...
Page 99 - ... same manner of the heliocentric and geocentric position of a planet with respect to the equator, and consequently of the heliocentric and geocentric right ascension and declination. We have still to speak of the commutation and the annual parallax of a planet. The commutation is the angle PST (Jig. 14), at the sun, S, obtained by deducting the heliocentric longitude of the earth from the heliocentric longitude of the planet. The annual parallax is the angle TPS. at the planet P, obtained by deducting...
Page 32 - The Pendulum as a Time-keeper. — The friction at the point of suspension, and the resistance of the air, soon destroy the motion of the pendulum and bring it to rest.

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