[sdiy] Obscure IC identification

[dj hohum]

I'm trying to identify some ICs. For some reason I thought that they
were a real time clock part, but, I'm not finding any data on this.
They are in a 16 pin dip.

They clearly display the national semiconductor logo, the old one that
looks like two tildes on top of each other. On the first line
following the logo they read /B218. Yes, the slash is part of the
number. On the second line they read 5814. Now I know that these parts
were not made in 1958 so I'm assuming that 5814 is a part of the part
number.

At this point I think this bag of chips qualifies as my most useless parts.

Any ideas?