James Nasmyth, Esq., on the Source of Light, 67 



space in which the light-yielding element may either abound 

 or be deficient, and so cause him to beam forth with increased 

 splendour, or fade in brilliancy, just in proportion to the 

 richness or poverty of this supposed light-yielding element as 

 may occur in those regions of space through which our sun, 

 in common with every stellar orb, has passed, is now passing, 

 or is destined to pass, in following up their mighty orbits. 



Once admit that this light-yielding element resides in 

 space, and that it is not equally diffused, we may then catch 

 a glimpse of the cause of the variable and transitory bright- 

 ness of stars, and more especially of those which have been 

 known to beam forth with such extraordinary splendour, and 

 have again so mysteriously faded away ; many instances of 

 which abound in historical record. 



Finally, in reference to such a state of change having 

 come over our sun, as indicated by the existence of a glacial 

 period as is now placed beyond doubt by geological research, 

 it appears to me no very wild stretch of analogy to suppose, 

 that in such former periods of the earth's history, our sun 

 may have passed through portions of his stellar orbit in 

 which the light-yielding element was deficient, and in which 

 case his brilliancy would have suffered the while, and an 

 arctic climate in consequence spread from the poles towards 

 the equator, and leave the record of such a condition in gla- 

 cial handwriting on the everlasting walls of our mountain 

 ravines, of which there is such abundant and unquestionable 

 evidence. As before said, it is the existence of such facts as 

 we have in stars of transitory brightness, and the above- 

 named evidence of an arctic climate existing in what are now 

 genial climates, that renders some adequate cause to be 

 looked for. I have accordingly hazarded the preceding re- 

 marks as suggestive of a cause, in the hope that the subject 

 may receive that attention which its deep interest entitles it 

 to obtain. 



This view of the source of light, as respects the existence 

 of the luciferous element throughout space, accords with the 

 Mosaic account of creation, in so far as that light is described 

 as having been created in the first instance before the sun 

 was called forth. 



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