Ahh, but Mark Womack argues that the whole point of Milton’s image of the “two-handed engine” is to leave us uncertain about its specific referent:

“The need to define ‘two-handed engine’ has put scholarly minds in a panic, producing a vast body of commentary ranging from the ingenious to the ludicrous. I submit that the panic exists not because critics do not understand the lines but because they do under-stand them . . . . Although no one can satisfactorily gloss ‘two-handed engine,’ every reader understands it. As we read these lines, the indicative adjective ‘that’ assures us that we do indeed know exactly what the ‘two-handed engine’ is. The lines thus give us momentary possession of knowledge that remains beyond our comprehension. By enabling us to incorporate something we do not actually comprehend into our minds, that line gives us a brief and trivial, but nevertheless genuine, experience of transcending the limits of the human mind.”