Excerpt: ...that the reason," asked Harry, "why a small piece of metal is always put across the ends of a horseshoe magnet when it is not in use?" "Yes." CHAPTER X STARTING ON THE VOYAGE TO THE WEST "If I remember correctly, you stated some time ago, Professor, that the barometer indicated the pressure of the atmosphere, and in that way it was useful in letting us know what the weather would be. Before we sail, would it not be well to make one of them? If we had possession of one of the articles, we might not have been ...
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Excerpt: ...that the reason," asked Harry, "why a small piece of metal is always put across the ends of a horseshoe magnet when it is not in use?" "Yes." CHAPTER X STARTING ON THE VOYAGE TO THE WEST "If I remember correctly, you stated some time ago, Professor, that the barometer indicated the pressure of the atmosphere, and in that way it was useful in letting us know what the weather would be. Before we sail, would it not be well to make one of them? If we had possession of one of the articles, we might not have been caught in the storm the first time we took out No. 3." "That is a good suggestion. I intended to propose that, because with the barometer and the compass we shall be equipped with two of the most useful instruments needed." "I cannot comprehend how the air pressure has anything to do with the weather. Is the air pressure really greater at one time than at another?" "Heated air ascends, does it not?" "Yes; I can understand that." "As it ascends it is, therefore, lighter at that point than normally. On the other hand, moist air is heavier than dry air. These two conditions would be indicated by the barometric column, would they not?" "I presume they would; but when the air is moisture laden we don't need a barometer to tell it is going to rain. We know it and feel it. What I particularly wanted to know was how the barometer by its actions would indicate it ahead for any length of time." "The barometer does not indicate with any degree of accuracy on land; but on sea it has a much better application. The instrument shows the present pressure of the atmosphere, and its variations correspond to atmospherical changes which have already taken place, the effects of which may follow their cause at a greater or less interval." "Then how could it be ascertained from the instrument when there would be a storm or rain?" "After a continuance of dry weather, if the barometer begins to fall slowly and steadily, rain will certainly ensue; but if the fine weather...
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Add this copy of The Wonder Island Boys to cart. $33.20, new condition, Sold by Booksplease rated 3.0 out of 5 stars, ships from Southport, MERSEYSIDE, UNITED KINGDOM, published 2017 by Pinnacle Press.
Add this copy of The Wonder Island Boys to cart. $45.96, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2017 by Pinnacle Press.
