Using Nikola Tesla photos in published works - Copyrighted or not?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mccauley, Daniel H" <daniel.h.mccauley@xxxxxxxx>

I'm curious to find out if there are any issues with using old photos of
Nikola Tesla in
published works.  According to the present copyright laws, any photo
captured or published prior to 1923
is now considered public domain.

Anyways, i'm not real sure on this issue and perhaps some of you others
who have written works using various
tesla photos etc... already know the answer to this.

Thing is, there are lots of photos being used everywhere, but nowhere
can i find an original source, etc... to provide credit (if i even need
to)

Thanks!

Dan