Scientific Dialogues: Intended for the Instruction and Entertainment of Young People, in which the First Principles of Natural and Experimental Philosophy are Fully Explained, Volumes 1-2Baldwin, Cradock, and Joy, 1815 - Science |
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24 hours 95 millions annual motion appear Aries astronomers axis called centre Charles clock comet consequently CONVERSATION dark days and nights degrees dial diameter discovered distance diurnal diurnal motion earth's orbit east ecliptic enlightened Ephemeris equa equal equator figure fixed stars full moon globe greater half harvest moon heavens hemisphere hence Herschel horizon inclination inhabitants James journey round Jupiter larger latitude Leap-Year less Libra light and heat longitude Mars Mercury meridian millions of miles minutes moon's nearer noon o'clock observe orbit parallel pass Plate polar circles position rays retrograde motion revolve rise and set rotation round the sun satellites Saturn seasons seen shadow shine sidereal day situated Solar System spectator summer sun and earth sun's superior planets supposed surface synodical month tance telescope tides tion tropic tropic of Cancer turn Tutor Venus vertical visible winter
Popular passages
Page 23 - In odoriferous bodies, such as camphor, musk, and asatoetida, a wonderful subtilty of parts is perceived, for though they are perpetually filling a considerable space with odoriferous particles, yet these bodies lose but a very small part of their weight in a great length of time. Again, it is said by those who have examined the subject with the best glasses, and whose accuracy may be relied on, that there are more animals in the milt of a single cod.fish, than there are...
Page 4 - •' are anxious that children should be conversant with mechanics, and with what are called the mechanical powers; Certainly no species of knowledge is better suited to the taste and capacity of youth, and yet it seldom forms a part of -early instruction. Every body talks of the lever, the wedge, and the pulley, but most people perceive that the notions which they have of their respective uses are unsatisfactory and indistinct, and many endeavour. at a late period of life, to acquire a scientific...
Page 167 - ... proportion as the circumference of the wheel is greater than that of the axle. If the...
Page 6 - ... terms which he is obliged to use. Ignorance of the language in which any science is taught, is an insuperable bar to its being suddenly acquired ; besides a precise knowledge of the meaning of terms, we must have an instantaneous idea excited in our minds whenever they are repeated ; and, as this can be acquired only by practice, it is impossible that philosophical lectures can be of much service to those who are not familiarly acquainted with the technical language in which they are delivered...
Page 161 - ... that there may be a balance between the power and the weight, the intensity of the power must exceed the intensity of the weight just as much as the distance of the weight from the prop exceeds the distance of the power.
Page 192 - When the wood does not cleave at any distance before the wedge, there will be an equilibrium between the power impelling the wedge downward and the resistance of the wood acting against...
Page 98 - There is no difficulty of conceiving that a body, as this inkstand, in a state of rest must always remain so, if no external force be impressed upon it to give it motion. But I know of no example which will lead me to suppose, that a body once put into motion would of itself continue so. Father. You will, I think, presently admit the latter part of the assertion as well as the former, although it cannot be established by experiment. Emma. I shall be glad to hear how this is. Father. You will not...
Page 24 - It has indeed been calculated that a particle of b_lood of one of these animalcula is as much smaller than a globe one-tenth of an inch in diameter, as that globe is smaller than the whole earth. Nevertheless, if these particles be compared with the particles of light, it is probable, that they would be found to exceed them in bulk as much as mountains do single grains of sand...
Page 85 - On the contrary, the narrower the base, and the nearer the line of direction is to the side of it, the more easily...
Page 162 - ... bones of a man's arm ; for when he lifts a weight by the hand, the muscle that exerts its force to raise that weight is fixed to the bone about one tenth part as far below the elbow as the hand is. And the elbow being the centre round which the lower part of the arm turns, the muscle must therefore exert a force ten times as great as the weight that is raised.