The forms of water in clouds & rivers, ice & glaciers / by John Tyndall ... with thirty-five illustrations drawn and engraved under the direction of the author.

  • Tyndall, John, 1820-1893.
Date:
1873
Catalogue details

Licence: Public Domain Mark

Credit: The forms of water in clouds & rivers, ice & glaciers / by John Tyndall ... with thirty-five illustrations drawn and engraved under the direction of the author. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    soon assure yourself that such springs are also fed by rain, which has percolated through the rocks or soil, and which, through some orifice that it has found or formed, comes to the light of day. 6. But we camiot end here. Whence comes the rain which forms the mountain streams P Observation enables you to answer the question. Bain does not come from a clear -sky. It comes from clouds. But what are clouds ? Is there nothing you are acquainted with which they resemble? You discover at once a likeness between them and the condensed steam of a locomotive. At every puff of the engine a cloud is pro- jected into the air. Watch the cloud sharply: you notice that it first forms at a little distance from the top of the funnel. Give close attention and you will sometimes see a perfectly clear space between the funnel and the cloud. Through that clear space the thing which makes the cloud must pass. What, then, is this thing which at one moment is transparent and invisible, and at the next moment visible as a dense opaque cloud ? 7. It is the steam or vapour of water from the boiler. Within the boiler this steam is transparent and in- visible; but to keep it in this invisible state a heat would hb required as great as that within the boiler. When the vapour mingles with the cold air above the hot funnel it ceases to be vapour. Every bit of steam shrinks, when chilled, to a much more minute particle of