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more exact, all later observations, besides
the earlier ones which have been hunted up
for the purpose, go to establish a true pe-
riodicity in the number of sun-spots. But
quite lately Schuster[6] has given reasons
for admitting a number of co-existent pe-
riods, of which the eleven-year period was
predominant in the nineteenth century.
In 1851 Lament, a Scotchman at Mu-
451
