Recreations in science; or, A complete series of rational amusement. By the author of Endless amusements (Google eBook)

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1830
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Page 194 - The nearer to mid.day or noon, the phases of the moon happen, the more foul or wet weather may be expected during the next seven days. 4. The space for this calculation occupies from ten in the forenoon to two in the afternoon. These observations refer principally to the summer.
Page 82 - By a proper use of the same instrument, every purpose of the peutagraph may also. be answered, as a painting may be reduced in any proportion required, by placing it at a distance in due proportion greater than that of the paper from the instrument. In this case a lens becomes requisite for enabling the eye to see at two unequal distances with equal distinctness, and in order that one lens may suit for all these purposes, there is an advantage in carrying the height of the stand according to the...
Page 194 - ... in the table. 6. Though the weather, from a variety of irregular causes is more uncertain in the latter part of Autumn, the whole of Winter, and the beginning of Spring ; yet in the main, the above observations will apply to those periods also. 7. To prognosticate correctly, especially in those cases where the wind is concerned, the observer should be within sight of a good vane, where the four cardinal points of the heavens are correctly placed.
Page 151 - ... in tone, by reason of a difference in thickness, and these may be placed one in the other without sensibly hurting the regularity of the taper form. The glasses being chosen, and every one marked with a diamond the note you intend it for, they are to be tuned by diminishing the thickness of those that are too sharp. This is done by grinding them round from the neck towards the brim, the breadth of one or two inches, as may be required ; often trying the glass by a...
Page 168 - ... is to be driven very cautiously, without breaking the grain of the wood, till the depth of the depression is equal to the subsequent prominence of the figures. The ground is then to be reduced, by planing or filing, to the level of the depressed part ; after which, the piece of wood being placed in water, either...
Page 151 - The advantages of this instrument are, that its tones are incomparably sweet beyond those of any other; that they may be swelled and softened at pleasure by stronger or weaker pressures of the finger, and continued to any length ; and that the instrument, being once well tuned, never again wants tuning.
Page 78 - To prevent the spreading of the colour, which, by blotting the parchment, detracts greatly from the legibility, the alkali should be put on first, and the diluted acid added upon it. The method found to answer best has been to spread the alkali thin with a feather over the traces of the letters, and then to touch it, gently, as...
Page 220 - ... and reappearance of objects, and of the change of shape of inanimate objects, which have been ascribed by the vulgar to supernatural causes, and by philosophers to the activity of the imagination. If in a dark night, for example, we unexpectedly obtain a glimpse of any object, either in motion or at rest, we are naturally anxious to ascertain what it is, and our curiosity calls forth all our powers of vision. This anxiety, however, serves only to baffle us in all our attempts.
Page 172 - ... which he makes a little charcoal fire ; a small bamboo blow-pipe, with which he excites the fire ; a short earthen tube or nozle, the extremity of which is placed at the bottom of the fire, and through which the artist directs the blast of the blow-pipe ; two or three small crucibles made of the fine clay of ant-hills, a pair of tongs, an anvil, two or three small hammers...
Page 188 - E class, by a knot projecting from the line ; the third, or I class, by the series of links, vulgarly called the drummer's plait ; the fourth, or M class, by a. simple noose ; the fifth, or Q class, by a noose with a line drawn through it ; the sixth, or U class, by a noose with a net-knot cast on it ; and the seventh, or Y class, by a twisted noose. The first letter of each class is denoted by the simple characteristic of its respective class ; the second by the characteristic, and a common knot...

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