 This is probably the effect of auroras boreales which are invisible, either on account of thick weather or day-light. Van Swinden says he seldom or never failed to observe aurora boreales immediately after any anomalous motion of the needle ; and concluded...  A System of Mechanical Philosophy - Síða 371eftir John Robison - 1822 - 50 síðurHeildartexta - Um bókina
 | Colin Macfarquhar, George Gleig - 1797 - 636 síður
...account of thick weather or day-light. Van Swinden fays, he feldom or never failed to obferve aurora; boreales immediately after any anomalous motion of...there had been one at the time, though he could not fee it. Since no needle but a magnetic one is affe&ed by the aurora borealis, we may conclude that... | |
 | Thomas Curtis - 1829 - 878 síður
...account of thick weather or day-light. Van Swinden says he seldom or never failed to observe aurora boreales immediately after any anomalous motion of...borealis, we may conclude that there is some natural connexion between this meteor and magnetism. This should farther incite us to observe the circumstance... | |
 | 1922 - 734 síður
...aurora borealis is most remarkable. . . . Van Swinden says he seldom or never failed to observe aurora boreales immediately after any anomalous motion of...been one at the time, though he could not see it. ... This should farther incite us to observe the circumstance formerly mentioned, viz., that the South... | |
 | 1922 - 736 síður
...aurora borealis is most remarkable. . . . Van Swinden says he seldom or never failed to observe aurora boreales immediately after any anomalous motion of...been one at the time, though he could not see it. ... This should farther incite us to observe the circumstance formerly mentioned, viz., that the South... | |
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