No More Learning

The           which Donne has in view is described by Du Bartas:

If heav'ns bright torches, from earth's Kidneys, sup
Som somwhat dry and heatfull Vapours up,
Th' ambitious lightning of their nimble Fire
Would suddenly neer th' Azure Cirques aspire:
But scarce so soon their fuming crest hath raught,
Or toucht the Coldness of the middle Vault,
And felt what force their mortall Enemy
In Garrison keeps there continually;
When down again towards their Dam they bear,
Holp by the weight which they have drawn from her.