Back (apologies for my handwriting!)
The text of the postcard is
I’m no scientist, or doctor, or a lot of things actually – but I think I’ve got it!
A perpetual motion machine!
You see, I have been under the weather and I swear, I go blow my nose to my heart’s content, then I wash my hands, leave the bathroom and boom! – time to blow the nose again.
So … you know … Somehow apply that to a perpetual motion machine.