I seem to remember that the Tel-Electric system was touted as being
compatible with the weather on ocean liners of the day because of their
brass roll.  No documentation on this, I just remember reading it
somewhere.  It was quite a concept and I found it hard to believe that
someone (or some company) would find it profitable to change a paper
roll concept into brass.

Also, as I remember, the rolls were in a special container probably to
contain the roll of brass sheeting from springing back to the straight
length it was cut from.   Spring (hardened) brass?  Most probably.
It surely wouldn't expand or shrink even in the worst of weather.
However, the wood in the piano... that's another subject!

Tim L'Amoureux