a mechanical device that blows a strong current of air; used to make a fire burn more fiercely or to sound a musical instrument
One who "bellows" can be considered "full of hot air"--Vulcan is both bellowing with ire ("a strong emotion toward some real or supposed grievance") and using a mechanical bellows to fan a fire that would help him make a brass net to catch his wife Venus and her lover Mars.
Poor Vulcan soon desir'd to hear no more,
He drop'd his hammer, and he shook all o'er:
Then courage takes, and full of vengeful ire
He heaves the bellows, and blows fierce the fire:
(classical mythology) the food and drink of the gods; mortals who ate it became immortal
A traditional ambrosia is a creamy fruit salad made of oranges, bananas, and shredded coconut--this could be what the Sun God's horses enjoy each day so that they have the vigor ("active strength of body") to pull the chariot across the sky each morning.
Ambrosia there they eat, and thence they gain
New vigour, and their daily toils sustain.
inclined to a healthy reddish color often associated with outdoor life
"Blush" is repeated many times here to emphasize the young boy's embarrassment at knowing nothing about love. In addition to the reddening of his face, the example sentence describes the redness of fruit touched by the sun and of eclipses touched by moonlight. With an innocence to match his blushing shame, the young boy tells the nymph to either leave him alone or he will leave.
The boy knew nought of love, and toucht with shame,
He strove, and blusht, but still the blush became:
In rising blushes still fresh beauties rose;
The sunny side of fruit such blushes shows,
And such the moon, when all her silver white
Turns in eclipses to a ruddy light.
"Vesper" means "evening" in Latin, and it is being used here to refer to the God of Evening, similar to how "helios" means "sun" in Greek, which makes Helios the Sun God (although he is often replaced by Apollo).
In towns, not woods, the sooty bats delight,
And, never, 'till the dusk, begin their flight;
'Till Vesper rises with his ev'ning flame;
From whom the Romans have deriv'd their name.
"Adamantine" and "implacable" could be synonyms--although the example sentence is using "adamantine" to describe a gate that is as hard as diamond, this is a gate of the Underworld, so it would be as "impervious to pleas, persuasion, requests, reason" as the Furies who are guarding it are incapable of being placated ("cause to be more favorably inclined").
Before a lofty, adamantine gate,
Which clos'd a tow'r of brass, the Furies sate:
Mis-shapen forms, tremendous to the sight,
Th' implacable foul daughters of the night.
Es (out) + face (appearance): to literally rub the face away, or rub off "the face of the earth"--which the Furies attempt to do to Thebes by shaking the palace, withering the grass, and infecting the king and queen with so much poison that one smashes his baby son against a wall and the other jumps into the sea with her other son.
And that revenge the Furies soon could grant:
They could the glory of proud Thebes efface,
And hide in ruin the Cadmean race.
money or property brought by a woman to her husband at marriage
For her my arms I willingly employ,
If I may beauties, which I save, enjoy.
The parents eagerly the terms embrace:
For who would slight such terms in such a case?
Nor her alone they promise, but beside,
The dowry of a kingdom with the bride.