Chemistry and Physics. 271 
it must necessarily exercise a powerful modifying influence over many 
meteorological phenomena 
ith reference to the differences between the maximum and minimum 
Observatories, it is remarked that a little consideration will serve to show 
that in the early stages, at least, of an inquiry like the present, little or 
no reliance could be placed on results derived from series of observations 
in which every seventh day, or fifty-two days in the year, were complete 
blanks. It has, in fact, been found that the omission of a single day in 
4 year will in some cases produce a very sensible effect upon the fing 
Tesults for the magnetic period. Hence it is that the author regards 
Some of the values he has obtained for this period as being open to cor- 
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' With regard to the probable cause of the variability of the short 
Period, the author remarks that the subject is one of great difficulty ; for, 
been applied to the explanation of astronomical phenomena. It is 
therefore not without any consi : 
Serve that the facts would perhaps be best explained by supposing— 
Ist. That a ring of nebulous matter exists differing in density or con- 
Stitution in different parts, or seve asses of such matter forming a 
discontinuous ring, circulating round the sun in a plane nearly coincident 
with the plane of the ecliptic, and at a mean distance from the sun of 
about one-sixth of the radius of the earth’s orbit. 
