One of the strongest images in this poem is the image of ripened (perhaps even over-ripened) fruit hanging on the trees. The heat has had its way with pears and grapes—they are ripe and ready to fall—but our speaker imagines that the dense heat and humidity are buoying the fruits up. H.D. is employing hyperbole here; obviously, no amount of humidity is stronger than gravity. But that's the power of the image that H.D. creates. Even an impossible image is incredibly vivid in this poem.
Lines 4-5: In these lines, we get the feeling that the fruit wants to drop, but can't. Darn thick air! You ruin everything.
Lines 6-9: Here we see the fruit as ripe (thanks to the heat—you're good for something, at least!). And we see the direct effect of the heat on the fruit. It's actually shaped it. And, if you're inclined to read some sexual connotations in the poem, here's where you might do it. Might we draw connections between ripening fruits and human "ripening"—or the maturing of bodies? Sexual desire may have the same effect on the human body that heat has on the fruit bodies.