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Article REMARKABLE SOLAR SPOTS. ← Page 3 of 5 →
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Remarkable Solar Spots.
by some recent observations . " We have been mucli disappointed , " says a reviewer of " Herschell ' s Astronomical Observations at the Cape , " " at finding that Sir John Herschel either has not observed , or has not described , the extraordinary structure of the fully luminous disc of the sun , as we and others have repeatedly seen it through Sir James South ' s great Achromatic , —a structure which should have been more distinctly seen at the Cape than in our climate . This structure resembles
compressed curd or white almond soap , or a mass of asbestos fibres , lying in a quaquaversus direction , and compressed into a solid mass . There can be no illusion in this phenomenon ; it is seen by any person with good vision , and on every part of the sun ' s luminous surface or envelope ; ancl we think affords an ocular demonstration that that surface or envelope is not a flame , but a soft-solid , or thick fluid , maintained in an inc : ndescent state by subjacent heat , and capable of being disturbed by
differences of temperature , and broken up as we see it when the sun is covered with spots or openings in the luminous matter . " Here , then , is a new point of view opened up in the sun ' s physical organization , —one which may serve as a basis for new theories , or the modification of old
ones . The great size , and undiminished dimensions of the last-mentioned spot at the time it was last observed , at the end of September , when it had approached within a short distance of the western margin of the sun , gave grounds to expect that it would again re-appear after the usual absence of about thirteen days and a half . On the morning of the 1 Sth October I descried it , for the first time , so far as a quarter of a digit from the eastern edgeof a narrow lenticular formwith three minute
, , dots , or black nuclei , discernible in the opening . From the obliquity of the view no correct estimate as yet could be made of its breadth , but its apparent length was 38 , 000 miles . It increased in size till the 17 th of October , when it became perfectly visible to the unassisted optics , having then a lineal extent of about 44 , 000 miles , or one twentieth part of the sun ' s diameter , an extent which it never afterwards exceeded . It contained four or five dark nuclei of considerable size , and a number of
smaller ones imbedded as before within the borders of the penumbra . The penumbra , though uneven and irregular , and daily changing its outline , by no means exhibited the extreme angular projections so prominently as on its previous appearance ; nevertheless , it was large enough to be seen by the naked eye as distinctly as before , —comprising an area of the sun ' s surface equal to 1 , 520 , 000 , 000 of square miles . Hence I am inclined to conclude that a spot of considerablless dimensions may
y be visible without the telescope to a good eye calculated for distant vision , ancl under favourable atmospheric circumstances . The present spot 1 clearly made out with the naked eye when within two digits of the sun ' s western verge , on the 24 th September , two or three days before its passing to the other side of the sun : a pretty large round spot in its vicinity , ( south-east ) which had broken out during the transit , might have contributed to the distinctness of the object , by apparently forming
a part of it—both spots being perceptible , as if in near contiguity , through a small opera glass , magnifying about three times . The next day nothing was discernible with the naked eye ; ancl the succeeding clay , 26 th October , exactly at noon , I saw with the telescope the last of the large spot , like a thin line or stroke upon the very verge of the sun ' s disc , as if it were part of the circumference ; it required minute ancl attentive inspection to detect it , but the air being clear I was confident in the ohservavoi ,. vi . 3 G
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
Remarkable Solar Spots.
by some recent observations . " We have been mucli disappointed , " says a reviewer of " Herschell ' s Astronomical Observations at the Cape , " " at finding that Sir John Herschel either has not observed , or has not described , the extraordinary structure of the fully luminous disc of the sun , as we and others have repeatedly seen it through Sir James South ' s great Achromatic , —a structure which should have been more distinctly seen at the Cape than in our climate . This structure resembles
compressed curd or white almond soap , or a mass of asbestos fibres , lying in a quaquaversus direction , and compressed into a solid mass . There can be no illusion in this phenomenon ; it is seen by any person with good vision , and on every part of the sun ' s luminous surface or envelope ; ancl we think affords an ocular demonstration that that surface or envelope is not a flame , but a soft-solid , or thick fluid , maintained in an inc : ndescent state by subjacent heat , and capable of being disturbed by
differences of temperature , and broken up as we see it when the sun is covered with spots or openings in the luminous matter . " Here , then , is a new point of view opened up in the sun ' s physical organization , —one which may serve as a basis for new theories , or the modification of old
ones . The great size , and undiminished dimensions of the last-mentioned spot at the time it was last observed , at the end of September , when it had approached within a short distance of the western margin of the sun , gave grounds to expect that it would again re-appear after the usual absence of about thirteen days and a half . On the morning of the 1 Sth October I descried it , for the first time , so far as a quarter of a digit from the eastern edgeof a narrow lenticular formwith three minute
, , dots , or black nuclei , discernible in the opening . From the obliquity of the view no correct estimate as yet could be made of its breadth , but its apparent length was 38 , 000 miles . It increased in size till the 17 th of October , when it became perfectly visible to the unassisted optics , having then a lineal extent of about 44 , 000 miles , or one twentieth part of the sun ' s diameter , an extent which it never afterwards exceeded . It contained four or five dark nuclei of considerable size , and a number of
smaller ones imbedded as before within the borders of the penumbra . The penumbra , though uneven and irregular , and daily changing its outline , by no means exhibited the extreme angular projections so prominently as on its previous appearance ; nevertheless , it was large enough to be seen by the naked eye as distinctly as before , —comprising an area of the sun ' s surface equal to 1 , 520 , 000 , 000 of square miles . Hence I am inclined to conclude that a spot of considerablless dimensions may
y be visible without the telescope to a good eye calculated for distant vision , ancl under favourable atmospheric circumstances . The present spot 1 clearly made out with the naked eye when within two digits of the sun ' s western verge , on the 24 th September , two or three days before its passing to the other side of the sun : a pretty large round spot in its vicinity , ( south-east ) which had broken out during the transit , might have contributed to the distinctness of the object , by apparently forming
a part of it—both spots being perceptible , as if in near contiguity , through a small opera glass , magnifying about three times . The next day nothing was discernible with the naked eye ; ancl the succeeding clay , 26 th October , exactly at noon , I saw with the telescope the last of the large spot , like a thin line or stroke upon the very verge of the sun ' s disc , as if it were part of the circumference ; it required minute ancl attentive inspection to detect it , but the air being clear I was confident in the ohservavoi ,. vi . 3 G