From A Defense of Rhyme by Samuel Daniel (1603)

And indeed I have wished that there were not that multiplicity of rhymes as is used by many in Sonnets, which yet we see in some so happily to succeed, and hath been so far from hindering their inventions, as it hath begot conceit beyond expectation, and comparable to the best inventions of the world: for sure in an eminent spirit, whom Nature hath fitted for that mystery, rhyme is no impediment to his conceit, but rather gives him wings to mount, and carries him, not out of his course, but as it were beyond his power to a far happier flight. All excellencies being sold us at the hard price of labor, it follows, where we bestow most thereof we buy the best success: and rhyme, being far more laborious than loose measures (whatsoever is objected), must needs, meeting with wit and industry, breed greater and worthier effects in our language. So that if our labours have wrought out a manumission from bondage, and that we go at liberty, notwithstanding these ties, we are no longer the slaves of rhyme, but we make it a most excellent instrument to serve us. Nor is this certain limit observed in Sonnets, any tyrannical bounding of the conceit, but rather a reducing it in girum and a just form, neither too long for the shortest project, nor too short for the longest, being but only employed for a present passion. For the body of our imagination, being as unformed chaos without fashion, without day, if by the divine power of the spirit it be wrought into an Orb of order and form, is it not more pleasing to nature, that desires a certainty, and comports not with that which is infinite, to have these closes....


Circle or circuit, that is, self-contained and perfect like a circle. The phrase "an Orb or order of form" that Daniel uses in the next sentence indicates what he means by "in girum." (Kallich, et al.).