I remember reading "anti-cult" literature in the 70s (maybe 80s - probably Dave Hunt) that quoted Russell, at the end of the nineteenth century, saying something along the lines of the dissolved into gases thing. Also that he seemed to deny a physical resurrection - that what the disciples saw was some kind of spirit creature with a fake body created and destroyed at each appearance (memory is foggy; quote might not be exact).
But since then I've learned to discount anything uttered in the past by even the founder* (not that I consider Russell the founder of the JWs: IMO, that distinction belongs to Rutherford). True authority lies in whatever is written in the latest Watchtower**. And nothing against a physical resurrection has been assumed by the WT since those ravings of Russell. They've never repudiated that view, AFAIK, but they've never ratified it either (again, AFAIK).
*In another thread I've discussed his 1914 date. That matters, IMO, because it is still foundational to JW teachings today.***
** I'm curious to see what is in the August Watchtower. Not that that is what actually matters. It's what they may have had to change that matters.
*** New light notwithstanding 😳