Scientific Dialogues for the Instruction and Entertainment of Young People: In which the First Principles of Natural and Experimental Philosophy are Fully Explained and IllustratedMechanics -- Astronomy -- Hydrostatics -- Pneumatics -- Optics -- Magnetism -- Electricity -- Galvanism. |
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angle appear atmosphere axis axle ball body bottom called cause centre of gravity centre of motion circle concave conductor consequently CONVERSATION convex convex lens degrees diameter direction distance diurnal motion earth eclipse electric fluid equal equator experiment explain fall feet figure fixed stars force fulcrum glass globe grains greater heat heavens heavier hydrometer inches inclined plane Jupiter kind length lens lever machine magnet matter means mechanical power mercury metal millions of miles moon move multiplied Natural Philosophy nature object observe orbit ounces Papa particles pass pendulum perpendicular piece planets poles pound pound weight pressure principle proportion pulleys quantity QUESTIONS FOR EXAMINATION quicksilver rays of light reason refraction retina rise round Saturn screw side space specific gravity square substances suppose surface tube valve velocity vessel wedge weight wheel wire
Popular passages
Page 421 - ... as the angle of reflection is always equal to the angle of incidence, the image for any point can be seen only in the reflected ray prolonged.
Page 140 - evidence of things not seen," in the fulness of Divine grace ; and was profound on this, the greatest concern of human life, while unable even to comprehend how the " inclination of the earth's axis to the plane of its orbit" could be the cause of the change of the seasons.
Page 174 - Venus a pea, on a circle of 284 feet in diameter ; the Earth also a pea, on a circle of 430 feet ; Mars a rather large pin's head, on a circle of 654 feet ; the Asteroids, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across...
Page 174 - Pallas, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across; Saturn a small orange, on a circle of four-fifths of a mile; Uranus a full-sized cherry, or small plum, upon the circumference of a circle more than a mile and a half, and Neptune a good-sized plum on a circle about two miles and a half in diameter.
Page 359 - The mercury is sustained in the tube by the pressure of the atmosphere on the surface of the fluid in the cup.
Page 96 - To ask or search I blame thee not ; for Heaven Is as the Book of God before thee set, Wherein to read his wondrous works, and learn His seasons, hours, or days, or months, or years. This to attain, whether Heaven move or Earth Imports not, if thou reckon right...
Page 282 - The horizontal distance to which a fluid will spout from a horizontal pipe in any part of the side of an upright vessel, below the surface of the fluid, is equal to twice the length of a perpendicular to the side of the vessel, drawn from the mouth of the pipe to a semicircle described upon the altitude of the fluid : and therefore the...
Page 390 - This will lead us to the explanation of one of the principal definitions in optics, viz. that the angle of reflection is always equal to the angle of incidence.
Page 242 - He first established the truth, that a body plunged in a fluid loses as much of its weight as is equal to the weight of an equal volume of the fluid!