I found this Stanley #39 folding rule last week.
Made of Ivory
sadly one part was broken years ago
(https://live.staticflickr.com/65535/54916344912_4c76125029_z.jpg) (https://flic.kr/p/2rELC5Y)nov144 (https://flic.kr/p/2rELC5Y) by Skip Albright (https://www.flickr.com/photos/skipskip/), on Flickr
(https://live.staticflickr.com/65535/54916344887_fedb89e575_z.jpg) (https://flic.kr/p/2rELC5x)nov146 (https://flic.kr/p/2rELC5x) by Skip Albright (https://www.flickr.com/photos/skipskip/), on Flickr
Out of all of them I own, I don't have any ivory ones. Probably my luck if I ever find 1 in the wild that it would be broken too. No matter- it's still a great find.
Neat find.
I wonder what the benefit of ivory was? Not, obviously, strength (note, though, that I've seen plenty of broken boxwood rules). Stability? Ease of reading? Or just bragging rights?
I have always assumed stability and a bit of bragging rights, but there may be a good reason.