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1858.] BEARINGS FROM THE RIFFELHORN. 145 iron is, but, like the magnetized steel needle, they are magnetic and polar. And these poles are irregularly distributed like the " consequent points" to which I have referred, and this is the reason why I have used the term. Professor Forbes, as I have already stated, was the first to notice the effect of the Riffelhorn upon the magnetic needle, but he seems to have supposed that the entire mass of the mountain exercised " a local attraction" upon the needle; (upon which end he does not say). To enable future observers to allow for this attraction, he took the bearing of several of the surrounding mountains from the Riffelhorn; but it is very probable that had he changed his position a few inches, and perfectly certain had he changed it a few yards, he would have found a set of bearings totally different from those which he has recorded. The close proximity and irregular distribution of its consequent points would prevent the Riffelhorn from exerting any appreciable influence on a distant needle, as in this case the local poles would effectually neutralize each other. f 1 ( 21.) . On the morning of the 15th ;the Riffelberg was swathed in a dense fog, through which heavy rain showered incessantly. Towards one o'clock the continuity of the gray mass was broken, and sky-gleams of the deepest blue were seen through its apertures; these would close up again, and others open elsewhere, as if- the fog were fighting for existence with the sun behind it. The sun, however, triumphed, the mountains came more and more into view, and finally the entire air was swept clear. I went up to the Gorner Grat in the afternoon, and examined more closely the magnetism of its rocks; here, as on the Riffelhorn, I found it most pronounced at the jutting pro-
Title | Tyndall, John, 1860, The Glaciers of the Alps. |
Alternative Title | Glaciers of the Alps. |
Creator | John Tyndall 1820-1893. |
Subject |
Glaciers -- Alps. Alps -- Description and travel. Color. |
Publisher | London : John Murray ... |
DateOriginal | 1860 |
Format | Tiff |
Extent | 33 cm. |
Identifier | col022 |
Call Number | QE576.T914 1860 |
Language | English |
Relation | Color Science |
Collection | Ice - 19th Century Polar Exploration & Glacial Studies |
Rights | http://www.lindahall.org/imagerepro/ |
Data Contributor | Linda Hall Library, LHL Digital Collections. |
Title | Page 145. |
Creator | John Tyndall 1820-1893. |
Subject |
Glaciers -- Alps. Alps -- Description and travel. Color. |
Publisher | London : John Murray ... |
Format | tiff |
Identifier | col022178 |
Call Number | QE576.T914 1860 |
Relation-Is part of | Is part of: The glaciers of the Alps : Being a narrative of excursions and ascents, an account of the origin and phenomena of glaciers, and an exposition of the physical princples to which they are related / By John Tyndall... |
Relation | Color Science |
Rights | http://www.lindahall.org/imagerepro/ |
OCR Transcript | 1858.] BEARINGS FROM THE RIFFELHORN. 145 iron is, but, like the magnetized steel needle, they are magnetic and polar. And these poles are irregularly distributed like the " consequent points" to which I have referred, and this is the reason why I have used the term. Professor Forbes, as I have already stated, was the first to notice the effect of the Riffelhorn upon the magnetic needle, but he seems to have supposed that the entire mass of the mountain exercised " a local attraction" upon the needle; (upon which end he does not say). To enable future observers to allow for this attraction, he took the bearing of several of the surrounding mountains from the Riffelhorn; but it is very probable that had he changed his position a few inches, and perfectly certain had he changed it a few yards, he would have found a set of bearings totally different from those which he has recorded. The close proximity and irregular distribution of its consequent points would prevent the Riffelhorn from exerting any appreciable influence on a distant needle, as in this case the local poles would effectually neutralize each other. f 1 ( 21.) . On the morning of the 15th ;the Riffelberg was swathed in a dense fog, through which heavy rain showered incessantly. Towards one o'clock the continuity of the gray mass was broken, and sky-gleams of the deepest blue were seen through its apertures; these would close up again, and others open elsewhere, as if- the fog were fighting for existence with the sun behind it. The sun, however, triumphed, the mountains came more and more into view, and finally the entire air was swept clear. I went up to the Gorner Grat in the afternoon, and examined more closely the magnetism of its rocks; here, as on the Riffelhorn, I found it most pronounced at the jutting pro- |
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