Cornerstone - closer to home

I'm working on this time capsule/cornerstone project.  Motivated by the box that I think is still the cornerstone on the historic site of Mishkan Israel in New Haven (1896).  I have a clipping from another cornerstone time capule for B'nai Shalom also of New Haven, now longer in existence (1895).

But really, can't I look into things closer to home.  Like Seattle?  Hey, De Hirsch Sinai had a cornerstone/time capsule commemorated in the above photograph for a building that they never did build (1901).  Pretty close in time.

And, the contents are at UW Special Collections.  What say, I go down there and check out what they have?

The experience from participating in Prof. Pianko's Digital Jewish History class last spring will help me as I spent quite a bit of time in Special Collections.

Also I have to find out what others have written about this.