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constitution ancl phenomena of the great luminary of our 
own system, and lead to the detection of changes at present 
not recognised, but which in their influence upon the earth 
may have an important bearing upon many questions of 
considerable interest in magnetical and meteorological science, 
and also upon the economy of the various forms of vegetable 
and animal life. The recent results of spectral analysis tend 
to show that the light of the sun has a general resemblance 
to that of the class of stars to which nearly all the known 
variables belong, and thus give additional weight to the 
probability that it may also be slightly variable. 
Professor Clifton made a communication, in which he 
endeavoured to show that the principles of the mechanical 
theory of heat afford an explanation of phenomena attending 
the production of light by bodies, either when this production 
of light is due to incandescence or to fluorescence. His 
remarks and explanations were illustrated by a series of 
highly interesting experiments. 
