Identify (very old) bricks with 2 studs I have this two bricks I got as a present a while ago, and wanted to know a bit more about them.

Things I noticed:


The material is not entirely hard as today's plastic bricks, some small marks can be seen on the righter one.
When they are put together, there's a little gap left between them, not smooth and tight as today's bricks.
I'm pretty sure it's very old.


What I'd like to know:


Year of creation (also estimated is great)
Material
Manufacturer
Anything else interesting about it :)


Thanks!
They're called MiniBrix. 


Year of creation: 1935.
Material: Rubber.
Manufacturer: Premo Rubber Company.
Watch my source informative video by JangBricks HERE, which tells the interesting history of toy bricks before LEGO ;).









Audiophile Bonus: Cool background music from the video.