No jocund health that Denmark drinks to-day,
But the great cannon to the clouds shall tell,
And the king's rouse the heavens all bruit again,
Re-speaking earthly thunder.
Claudius proposes a celebration because of this good news. A drinking fest, that will shake the earth to the heavens (the divine right of Kings and natural order etc). Note that this is the only point in the play that allows Claudius to be construed as an alcoholic, which is how Hamlet later depicts him. (Many actors have, in fact, played Claudius in just such a manner.) The play offers little evidence for Claudius actually being a drunkard, and Hamlet is hardly an unbiased party. Indeed, apart from his guilt in the murder of his brother, Claudius is shown to be a rather capable ruler.
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