On Sun, 31 Aug 2003 19:10:28 -0400, Helen Scarth
wrote:

,;Could someone please have a look at this picture -
,;http://www.treadles.ca/website/plate.jpg and see if they can tell if
,;it's brass plating over steel/nickel/whatever, or vice versa. One
,;word of warning though, the picture is 381K in size.

There is no question in my mind that you have a brass (or bronze)
plate with a bit of ("white") plated metal left. I would assume the
plate is nickel although it could be chromium.

If you can find a friendly analytical chemist they could answer your
question while you wait.
,;
,;It's a slide plate from an 1870 Singer sewing machine and I'm
,;intrigued about it because earlier machines had what I'd assumed to be
,;solid brass plates until this one appeared with the two colours.
,;
,;I've tried scratching it with a pin, sliding my fingernail across the
,;two colours and checked it with a 30 power magnifying glass, all with
,;inconclusive results.
,;
,;Hopefully someone here will have far more knowledge of metallurgy and
,;better eyes than I do. Larger scans available on request.
,;
,;Helen