Conversations on Natural Philosophy, in which the Elements of that Science are Familiarly Explained

_Mrs. B._ You may easily imagine, what enormous weights may be raised by levers of this description, for the longer, when compared with the other, that arm is to which the power...

_Emily._ I believe I do, though I feel rather at a loss to explain it. Is not a fluid level when its surface is smooth and flat, as is the case with all fluids, when in a state...

_Mrs. B._ In speaking of the air, I think we defined elasticity to be a property, by means of which bodies that are compressed, return to their former state. If I bend this cane...

_Emily._ And if any cause should destroy the centripetal force, the centrifugal force would alone impel the body, and it would, I suppose, fly off in a straight line from the ce...

_Mrs. B._ Let us begin by examining the reflection of a convex mirror. This is formed of a portion of the exterior surface of a sphere. When several parallel rays fall upon it,...

_Mrs. B._ It expands by wetting, and contracts in drying; it is also more soft and pliable when wet, so that I can make it fit better, and when dry, it will be tighter. We must...

_Mrs. B._ This you will see exemplified in figure 2, in which the earth is represented, as it is situated on the 21st of June, and England receives less oblique, and consequentl...

In fig. 2, S represents the sun, which pours forth rays of light in straight lines, in every direction. E is the earth, and M the moon. Now a ray of light coming from one extrem...

_Mrs. B._ And I hope to convince you, that the sense of sight, is so likewise. The nerves, which constitute the sense of sight, are not different in their nature from those of t...

_Caroline._ Yet surely, Mrs. B., there are other properties which are essential to bodies, besides those you have enumerated. Colour and weight, for instance, are common to all...

_Mrs. B._ Some of the planets are proved to be larger than the earth; it is only their immense distance from us, which renders their apparent dimensions so small. Now, if we con...

_Mrs. B._ Do not forget that the direct rays of light which pass from the sun to the earth, do not meet our eyes, excepting when we are looking at that luminary, and thus interc...

_Mrs. B._ Just so, my dear. The composition of the two winds, north and east, produces a constant north-east wind; and that of the two winds, south and east, produces a regular...

_Mrs. B._ May not the inhabitants of Mercury, with equal plausibility, pity us for the insupportable coldness of our situation; and those of Jupiter and Saturn for our intolerab...

18. (Pg. 29) The air is more dense near the surface of the earth, and decreases in density as you ascend, how is this accounted for, and to what is it compared?

_Mrs. B._ Invisible, I allow; but we must not imagine that what we no longer see no longer exists. Were every particle of matter that becomes invisible annihilated, the world it...

There is a question I am very desirous of asking you, respecting fluids, Mrs. B., which has often perplexed me. What is the reason that the great quantity of rain which falls up...

_Mrs. B._ It is a double microscope, (fig. 6.) in which you see, not the object A B, but a magnified image of it, _a b_. In this microscope, two lenses are employed; the one, L...

_Caroline._ I think the effect is very sensible, for, in looking through the glass of the window, I see objects very much distorted; articles which I know to be straight, appear...

Those circles which divide the globe into two equal parts, such as the equator and the ecliptic, are called greater circles; to distinguish them from those which divide it into...

OF LUMINOUS, TRANSPARENT, AND OPAQUE BODIES. OF THE RADIATION OF LIGHT. OF SHADOWS. OF THE REFLECTION OF LIGHT. OPAQUE BODIES SEEN ONLY BY REFLECTED LIGHT. VISION EXPLAINED. CAM...

_Mrs. B._ Certainly. The screw, with the addition of the lever, forms a very powerful machine, employed either for compression or to raise heavy weights. It is used by book-bind...

HARMONY. A combination of musical sounds, produced by vibrations which bear a certain ratio to each other; and which thence affect the mind agreeably, when heard at the same tim...

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The above works will be found useful and very valuable as works of reference, as well as for schools. The Maps, composing the Atlases, will be found equal in execution and corre...

Although there are many worthless School Books, there are but few which are equally impure and inaccurate with the original editions of Goldsmith's Histories, for the use of Sch...