Alchemy, hmm? I understand why he had to use “separate” for first getting out the dirt, then the oxygen, but what did he use “combination” on? Ryoma said that “transformation” is one alchemical skill, to change the form of a thing. But…all of it seems to be changing the form, through mixing, combining, separating…I don’t think the author thought this went out, just wanted to show off alchemy. TBH, I think he’s doing more of chemistry than alchemy, but I guess they could be considered related.