Lovely Set of 3 Antique Drafting Triangles silver pheasant easy to open and holds

easy to open and holds tightly closed

and a cut upper right corner

Dimensions:

and the name of its proud maker John Jenkins in capital letters across the back with the year framed in scrolls

Lovely Set of 3 Antique Drafting Triangles silver pheasant easy to open and holdsI can't resist these when I come across them; they just make me want to sit down and make geometric drawings. I found these three together and have to think they have been together for a long time, together making an excellent set. The dark one was once marked as a ruler on the hypotenuse; now mostly faded, but a few inches remain visible. The scalene triangle is marked with a Sphynx logo, which I have not been able to place. I'd guess all three date