huh, interesting bad weather windscreens! Thanks to Steve, I learned about it, a Cambridge windshield, they were mostly used on sporting type cars

https://forums.aaca.org/topic/341211-period-images-to-relieve-some-of-the-stress/page/336/

This is known as a Cambridge windshield and it's made of either isinglass or celluloid - probably isinglass (originally made from fish bladders) in this case. 

 The earliest mention dates from 1909 and it became a generic term, like the California top became. https://forums.aaca.org/topic/448353-cambridge-windshield/ 

 https://www.shorpy.com/node/24210