I figured I'd necro this rather than create a new thread.
Let us assume that Herr Klaproth meets Mr. Wedgwood and becomes interested in photography. The chemist attempts to document the extraction or uranium from pitchblende in photographs, or rather silver nitrate on leather being exposed to sunlight minus the silhouette of the photographed objects. He finds that the raw ore exposes the nitrate, as does the extracted uranium. He later exposes both without sunlight, and finds that a sort of "invisible glow" emanates from the rocks. As the leading chemist of Germany, he publishes, making famous both the *radioactive nature of uranium and the photographic process used to document it.
Now all of Europe is familiar with Herr Klaproth's magic powder, and leading scientists go about trying to explain this newly found *radioactivity. As a result, we might get the earlier production of uranium metal, potentially usable for artillery shells and potentially making Canada very, very rich. Charlatans left and right start selling the powder, claiming that its invisible glow is the "essence of life," and I imagine some royalty would buy into it. But without the development of a theory of radioactive decay and thus the discovery of isotopes, the only radioactive substance known to man will remain U-238. Despite marginally better artillery as a result of greater interest in uranium and a few gimmicks with yellow cake and silver nitrate, I can't think of any uses of U-238 in the early 19th century.
The other side of this discovery would be a greater interest in photography to find other *radioactive substances. Aside from perhaps monazite ore and the resulting discovery of *thorium, it's not really possible that any other elements would be discovered. However, the new importance of silver nitrate would certainly speed the development of photographic plates for detection of *radioactivity and, for consumers, amateur photography. Perhaps photography gains a ten- or twenty-year advance over OTL.
Dies this sounds somewhat plausible? What would the ramifications of such a discovery be?