A manual of natural philosophy, by J.L. Comstock and R.D. Hoblyn

Front Cover

Other editions - View all

Common terms and phrases

Popular passages

Page 303 - Mars a rather large pin's head, on a circle of 654 feet; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from...
Page 317 - Different opinions have been advanced by astronomers respecting the cause of these appearances. By some, they have been regarded as clouds, or as openings in the atmosphere of the planet, while others imagine that they are the marks of great natural changes, or revolutions, which are perpetually agitating the surface of that planet. It is, however, most probable, that these appearances are produced by the agency of some cause, of which we, on this little earth, must always be entirely ignorant.
Page 190 - ... came to prepare with all haste for a storm. The barometer had begun to fall with appalling rapidity. As yet, the oldest sailors had not perceived even a threatening in the sky, and were surprised at the extent and hurry of the preparations: but the required measures were not completed, when a more awful hurricane burst upon them than the most experienced had ever braved. Nothing could withstand it; the sails already furled and closely bound to the yards, were riven away in tatters; even the bare...
Page 202 - I considered how to produce rotative motions from them in the best manner ; and amongst various schemes which were subjected to trial, or which passed through my mind, none appeared so likely to answer the purpose as the application of the crank in the manner of the common turning-lathe (an invention of great merit, of which the humble inventor, and even its era, are unknown).
Page 459 - A sphere is a solid bounded by a curved surface, every point of which is equally distant from a point within called the center.
Page 243 - The transparent body through which the light passes is called the medium, and it is found in all cases, that where a ray of light passes obliquely from one medium into another of a different density, it is refracted, or turned out of its former course.
Page 471 - SKY, the blue expanse of air and atmosphere. The azure colour of the sky is attributed, by Sir Isaac Newton, to vapours beginning to condense there, and which have got consistence enough to reflect the most flexible rays. SNOW, a well known substance, formed by the freezing of the vapours in the atmosphere. It differs from hail and hoarfrost, in being as it were crystallized, which they are not. SOLID, in...
Page 310 - It is a fact, not a little interesting to Englishmen, and, combined with our insular station in that great highway of nations, the Atlantic, not a little explanatory of our commercial eminence, that London occupies nearly the center of the terrestrial hemisphere.
Page 202 - ... ascent,) I proposed to employ two engines, acting upon two cranks fixed on the same axis, at an angle of 120 to one another, and a weight placed upon the circumference of the flywheel at the same angle to each of the cranks, by which means the motion might be rendered nearly equal, and only a very light fly-wheel would be requisite.
Page 301 - ... who could foretell eclipses, and who discovered the precession of the equinoxes, still believed that the earth was at rest in the centre of the universe, and that all the hosts of heaven performed a daily revolution about it as a centre. It usually happens in scientific progress, that when a great fact is at length discovered, it approves itself at once to all competent judges. It furnishes a solution to so many problems, and harmonizes...

Bibliographic information