First lessons in philosophy, or, The science of familiar things; in which the principles of natural and experimental philosophy are systematically ... the properties and uses of familiar things - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1857 Excerpt: ...streams of water, made for the purpose of conveying heavy goods from one place to another by means of barges. In order that the barges may sail in both directions of the canal, it is necessary that the water in the canal should be level; this is usually effected by means of locks, or flood gates. This figure represents a lock, made at a place where there is a sudden fall of the channel of the canal. A B and c D are the two gates, which completely intercept the course of the water, but at the same time admit of being opened and closed; A H is the level of the water in that part of the canal lying above the gate A B, and F G the level lying below the gate c D: now, when a barge is about to pass from A H to F G, a side sluice, not shown in the figure, is first opened, which allows the water to flow from A H into the space A E F c, between the gates, until it attains the common level, H A c; the gate A B is then opened, and the barge floats into the space between the gates; the gate A B, as well as the sluice, is now closed, and another sluice is opened, which allows the water to flow from the space A E F c until it comes to the common level, E F G; the gate c B is then opened, and the barge floats out of the locks along the canal. By reversing the steps of this process, the barge may be floated in the contrary direction. A horse is usually employed to pull the barge through the LXVI. The rain which falls upon hills and mountains forms springs and rivers. The greater portion of the rain which falls upon a hill flows on the surface to the valleys, and forms streams, or rivers, which run towards the ocean; but a certain portion of the water which falls upon a hill penetrates or filters through the porous or loose substances, A, of which the side of the hill is co...
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