"I would land-damn him."
As 'land-damn' seems to be an unknown term, it might be better to read, with Collier's folio, lamback, derived perhaps from lambiccare, It. There is also a vulgar term lambaste. 'Damn' was probably suggested by the same word in the preceding line.
Sc. 3.
"We have always truly served you and beseech you."
"They have been absent. 'Tis good speed, and foretells."
We might also read it; or, with Pope, 'This good speed.'