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<p>[QUOTE=&quot;Kentucky, post: 1806707, member: 33176&quot;]I am a chemist also, but an organic chemist with an interest in inorganic chemistry and coins.&nbsp; I found some disagreement with the presentation and am not sure if I am just being picky or suspicious because of other inaccuracies.&nbsp; On slide 4 we are told that some bronze disease is caused by the production of acid internally!!?&nbsp; What does that mean?&nbsp; Slide 9 assures us a patina is oxidation, but he doesn&#039;t mention that many acids are &quot;oxidizing&quot; acids, so can acids cause patina to form.&nbsp; He also mentions a 5% molal solution, which is like saying 5 cents dollars.&nbsp; Finally he tells us on slide 19 that ethanol is a dangerous chemical and difficult to purchase...maybe if you are under 21, those over 21 can purchase 40 or 50% solutions as Vodka (whatever brand you like) or as 95% Everclear Pure Grain Alcohol.</p><p>&nbsp;</p><p>Patina, corrosion, verdigris are mostly the same animal&nbsp; since it is not a well defined animal, and a lot depends on surface factors, crystal growth and density of deposition, which is way beyond my scope, but at least I know it is.&nbsp; All this being said, I appreciate a good patina but decry verdigris.[/QUOTE]</p><p><br /></p>

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