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Article REMARKABLE SOLAR SPOTS. ← Page 5 of 5
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Remarkable Solar Spots.
without entering into more minute details—which , from the desire of substantiating my inferences and comments , I have perhaps too much indulged in—it may suffice to state that the spot had again contracted in dimensions during its absence , and assumed latterly a somewhat triangular shape . Its square contents , or area , were therefore necessarily less , though one side of its triangle measured more than the length of its former diameter . On the 17 th and 18 thit was visible to the naked
, very eye : cloudy weather intervened thereafter , but it must have disappeared at the sun ' s western edge on the 21 st or 22 nd at furthest . Its return , should it not be obliterated , will occur on the 4 th or Sth of December . It has now reached a continuation of ninety-five days , or thereabouts ; aduration longer than any hitherto upon record , —the spot of 1676 being the longest in duration recorded , so far as I am aware , —such , at least , I think I have established to be tlie fact . I am not very sure , however , that cluster mentioned
a spot or in my former notice as visible to the naked eye on the 29 th and 31 st July last , was not the Protean precursor of the two contiguous spots of the 19 th August . A rough draft which I find I had made of it gives its position within a circle a little past the centre of the sun , going westwards ; this would make it within six days , or so , of its disappearance , which would therefore take place on the 4 th of August—reckoning from the 30 th July , the intermediate day . As a spot takes about thirteen days and a half in its apparent transit across the disc , we should then have the 17 th or 18 th of August for its
reappearance on the verge of the sun ' s eastern limb—which brings it close enough to the 19 th , the time when the two spots were first observed , and these must then have come some little way on to be distinctly seen . Not having regularly noted the precise period of the July spot , it might be presuming too much on the supplied data to draw any positive conclusion as to its identity with that of August , but I am strongly impressed with the persuasion that it was the same , a result which , if established ,
would add another month to the entire duration of the spot we have been considering . We have no reason to doubt that a spot should continue as long , ancl much longer—say even a year or more—when we consider the comparatively vast scale on which the solar evolutions are performed . A tornado of a few days duration on our earth might be considered long ; but a similar physical phenomenon on the sun is not to be limited to a few months as an extraordinary period of duration . It
is probable , indeed , that the want of sufficient observations alone has hitherto restricted our knowledge of the real continuance of some of the solar spots , as well as of their more particular phases and developements . An association , however , I understand has lately been formed for the express purpose of observing the solar spots in a more systematic manner than has yet been attempted ; ancl as , no doubt , the members consist of men of scientific accomplishments and experience , we may look to the result of their conjoint efforts for a mass of interesting information and instruction , greater than has hitherto been , or than could be obtained by mere individual and isolated observation . PILGRISI .
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
Remarkable Solar Spots.
without entering into more minute details—which , from the desire of substantiating my inferences and comments , I have perhaps too much indulged in—it may suffice to state that the spot had again contracted in dimensions during its absence , and assumed latterly a somewhat triangular shape . Its square contents , or area , were therefore necessarily less , though one side of its triangle measured more than the length of its former diameter . On the 17 th and 18 thit was visible to the naked
, very eye : cloudy weather intervened thereafter , but it must have disappeared at the sun ' s western edge on the 21 st or 22 nd at furthest . Its return , should it not be obliterated , will occur on the 4 th or Sth of December . It has now reached a continuation of ninety-five days , or thereabouts ; aduration longer than any hitherto upon record , —the spot of 1676 being the longest in duration recorded , so far as I am aware , —such , at least , I think I have established to be tlie fact . I am not very sure , however , that cluster mentioned
a spot or in my former notice as visible to the naked eye on the 29 th and 31 st July last , was not the Protean precursor of the two contiguous spots of the 19 th August . A rough draft which I find I had made of it gives its position within a circle a little past the centre of the sun , going westwards ; this would make it within six days , or so , of its disappearance , which would therefore take place on the 4 th of August—reckoning from the 30 th July , the intermediate day . As a spot takes about thirteen days and a half in its apparent transit across the disc , we should then have the 17 th or 18 th of August for its
reappearance on the verge of the sun ' s eastern limb—which brings it close enough to the 19 th , the time when the two spots were first observed , and these must then have come some little way on to be distinctly seen . Not having regularly noted the precise period of the July spot , it might be presuming too much on the supplied data to draw any positive conclusion as to its identity with that of August , but I am strongly impressed with the persuasion that it was the same , a result which , if established ,
would add another month to the entire duration of the spot we have been considering . We have no reason to doubt that a spot should continue as long , ancl much longer—say even a year or more—when we consider the comparatively vast scale on which the solar evolutions are performed . A tornado of a few days duration on our earth might be considered long ; but a similar physical phenomenon on the sun is not to be limited to a few months as an extraordinary period of duration . It
is probable , indeed , that the want of sufficient observations alone has hitherto restricted our knowledge of the real continuance of some of the solar spots , as well as of their more particular phases and developements . An association , however , I understand has lately been formed for the express purpose of observing the solar spots in a more systematic manner than has yet been attempted ; ancl as , no doubt , the members consist of men of scientific accomplishments and experience , we may look to the result of their conjoint efforts for a mass of interesting information and instruction , greater than has hitherto been , or than could be obtained by mere individual and isolated observation . PILGRISI .