The Elements of Natural Or Experimental Philosophy, Volume 4

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T. Cadell and W. Davies, 1803
 

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Page 98 - To understand this, we must observe, what has been already mentioned, that the axis of the earth is inclined to the plane of its orbit 23J°, and it keeps always parallel to itself; that is, it is always directed to the same star.
Page 90 - K ; and so the sun's attraction being more than sufficient to keep the planet from going off at B, it describes the same orbit over again by virtue of the same forces or powers. A double projectile force will always balance a quadruple power of gravity. Let the planet at B have twice as great an impulse from thence towards X as it had before ; that is, in the same length of time that it was projected from B to...
Page 233 - BD ; then if the Eye is at rest at A, the Object must appear in the Direction AC, whether Light be propagated in Time or in an Instant. But if the Eye is moving from B towards A, and Light is propagated in Time, with a Velocity that is to the Velocity of the Eye, as CA to BA; then Light moving from C to A...
Page 233 - Light; then it was easy to conceive, that the Particle of Light at C (by which the object must be seen when the Eye, as it moves along, arrives at A) would pass through the Tube BC, if it is inclined to BD in the Angle...
Page 234 - A, with the same velocity; then the tube must be inclined in the angle BDC. Although therefore the true or real place of an object is perpendicular to the line in which the eye is moving, yet the visible place will not be so, since that, no doubt, must be in the direction of the tube; but the difference between the true and apparent place will be (caeteris paribus) greater or less, according to the different proportion between the velocity of light and that of the eye.
Page 366 - December, 1 798, about eight o'clock in the evening, a very luminous meteor was observed in the heavens, by the inhabitants of Benares and the parts adjacent, in the form of a large ball of fire ; that it was accompanied by a loud noise, resembling thunder ; and that a number of stones...
Page 395 - Whitehurft ufed, vibrating 42 and 84 times in a minute of mean time, in the latitude of London, at 113 feet above the level of the fea, in the temperature of 60°...
Page 233 - DBC, and accompanies the eye in its motion from B to A; and that it could not come to the eye, placed behind such a tube, if it had any other inclination to the line BD.
Page 291 - ... confequently, if the obfervation be made in the forenoon, the time, thus found, muft be taken from 24 hours, and the remainder will be the apparent time from the noon of the preceding day. Example. On the 5th of March 1780, in the afternoon, in latitude 16° 24' north, and longitude 138" eaft, the altitude of the fun's lower limb was obferved to be 47° 8
Page 135 - But the moon's motion is so nearly in the ecliptic, that we may consider her for the present as moving in it. Now the different parts of the ecliptic, on account of its obliquity to the earth's axis, make very different angles with the horizon as they set or rise.

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