The Clarke tin whistle company was established in 1843. From then until (roughly) 1870, the tin-plate that they used was sheet iron that was, presumably, hot-dipped, into a vat of molten tin, then rolled thru a roller to squeeze off excess tin and create a uniform thickness/coating. Does anyone have one of these whistles from the original 30 year run of production, 1843 - 1870 ? If so, could you post pictures of the whistle along with any details that you feel are pertinent to my inquiries or any details that you think may be of interest to this forum/query? After 1870, they likely switched to sheet steel, hence the questions.
The only whistle I have that’s about that old you can see here.
Fourth picture down. It may or may not be a Clarke, but is certainly brass. The other old whistles and especially the rolled / pressed steel ones are all undoubtedly post-1870s. I’ve read that Clarke made some whistles in brass early on, so who knows!
Take a look there and here as well.