Category: Science - Physics
A. The rays of the sun, collected by the Burning Glass, are all _bent to one point_, called the "focus;" thus the heat and light, (which should be diffused over the _whole_ glass,) being gathered together into one point, are very greatly increased.
A. Because the water in the saucer is _supped up_ by the mould (through the hole at the bottom of the flower-pot), and is transferred to the stem and leaves of the plant by CAPI...
30. CHAPTER XXVII.A. Because the pupil (which _contracted_ in the bright room) does not _dilate instantaneously_; and the contracted pupil is not able to _collect rays enough_ (from the dark road...
19. CHAPTER XVI.A. Yes; when the tea-pot is _set on the hob "to draw,"_ the black _earth_ is the _best_, because it _absorbs heat_: but when the tea-pot is _not_ set on the hob, the bright _met...
6. CHAPTER III.A. Many things, when their chemical constitution is changed, (either by the abstraction of some of their gases, or by the combination of others not before united,) evolve _heat_...
25. CHAPTER XXII.A. If a bladder _half full of air_ (tied tight round the neck), were laid before a _fire_, the heat of the fire would expand the air so much, that the bladder would soon be _ent...
14. CHAPTER XI.A. When the _surface of the earth_ is _warmer than the air_, the vapour of the earth (being condensed by the chill air) becomes _mist or fog_. But when the _air_ is _warmer than...
5. CHAPTER II.A. Yes; they often run a considerable way along the ground, then _stop_ for a little time, and _burst in numberless pieces_: sometimes _each of these pieces_ will explode; and a...
21. CHAPTER XVIII.A. The blood derives its redness from the _oxygen_ of the air inhaled; but, as the air in close rooms and cities _is not fresh_, it is _deficient in oxygen_, and cannot turn the...
16. CHAPTER XIII.A. _Wood is a bad conductor of heat_; and, therefore, heat does not traverse freely through it: hence, though one end of a stick be blazing-hot, the other end may be quite cold.
12. CHAPTER IX.A. Chestnuts contain a great deal of air, which is expanded by the heat of the fire; and, as the thick rind prevents the air from escaping, it violently _bursts through, slittin...
22. CHAPTER XIX.A. If a pit or well contain carbonic acid, _a candle_ (let down into it) _will be instantly extinguished_. The rule, therefore, is this--Where a _candle will burn, a man can liv...
7. CHAPTER IV.A. When the hot air of the chimney has been cooled by the _external_ air, it can no longer _buoy up_ the solid smoke; so it falls to the earth in condensed flakes, called "blacks."
26. CHAPTER XXIII.A. Because the mercury in the tube _rises and falls_, as the air becomes lighter or heavier: and we can generally tell by the _weight_ of the air, what kind of weather to expect.
29. CHAPTER XXVI.Q. _In winter time, FOOT-MARKS and WHEEL-RUTS are often covered with an icy NET-WORK, through the interstices of which the soil is clearly seen,--WHY does the water freeze in NE...
9. CHAPTER VI.A. Yes. Whenever blood _flows from a wound_, some _vein_ must be divided; and as you cannot insert a needle into _any part of the body without bringing blood_, therefore these l...
27. CHAPTER XXIV.A few years ago, some fishermen (who wintered at Nova-Zembla), after they had been shut up in a hut for several days, _opened the window_, and the cold external air rushing in,...
8. CHAPTER V.A. 1st--When the _hydrogen_ of the tallow and _oxygen_ of the air _condense into water_, a _vacuum_ is made; and the air is disturbed, as a _pond_ would be, if a pail of _water_...
31. CHAPTER XXVIII.A. The _keys of the piano_ (being struck with the finger) lift up a little hammer which _knocks against a string_; and the vibration thus produced, sets in motion the sound-wave...
20. CHAPTER XVII.A. The water _nearest the fire is first heated_, and (being heated) _rises to the top;_ other cold water succeeds, is _also_ heated, and rises in turn; and this interchange keep...
15. CHAPTER XII.A. The air contains heat, and changes the _surface of the water into vapour_; this vapour (blending with the air) _is soon wafted away_; while _fresh_ portions of air _blow over...
17. CHAPTER XIV.A. _Black cloth absorbs_, but does not _conduct heat_: thus, if black cloth be laid in the sun, _it will absorb the rays_ very rapidly; but if _one end of the black cloth_ be ma...
28. CHAPTER XXV.11. CHAPTER VIII.A. They take a piece of dry wood (sharpened to a point), which they rub quickly up and down a _flat piece_, till a _groove_ is made; and the _saw-dust_ (collected in this groove...
13. CHAPTER X.A. The iron stove _contracts again_, as soon as the fire is removed; and (as it shrinks into a smaller space) the parts _rub against each other again_, and the _bricks are again...
18. CHAPTER XV.A. If a piece of tin were thrust _into_ a fire, it would be _in actual contact with the fire_; but if it be _held before a fire_, the heat of the fire _falls upon it in rays_.
24. CHAPTER XXI.A. Perhaps _all_ the ghost stories (which deserve any credit at all) have arisen from the ignited gas of church-yards lurking about the tombs, to which _fear_ has added its own...
23. CHAPTER XX.A. Because the metal wire is a very _rapid conductor of heat_; and when the flame of burning gas in the lamp reaches the wire gauze, the heat (which is needful to produce flame)...
10. CHAPTER VII.A. They used to place a soft iron nail upon their anvil; strike it two or three times with a hammer; and the point became _sufficiently hot to light a brimstone match_.
4. CHAPTER I.A. The rays of the sun, collected by the Burning Glass, are all _bent to one point_, called the "focus;" thus the heat and light, (which should be diffused over the _whole_ glas...
3. PART I.1. PART I.--HEAT.2. PART II.--AIR.