Hmmm. Not so fast, hiphope.
I had originally said melodian, and there is some confusion about the relationship of a melodeon to a harmonium or an accordian. A melodeon accordian, according to Wikipedia, has push buttons instead of keys. A melodeon organ, says Wikipedia, has pedals that drive vacuum bellows, while the harmonium uses pedals to drive pressure bellows. They both look pretty much the same.
Perhaps it’s two words for the same thing. I’m not clear on which one Ginsberg had and they both look the same. The difference is on the inside.
PS, Harp was the first one to say harmonium. I had said melodian until I did further research. Now I don’t know which is true.