YA mystery from the 70' or 80's. A group of kids solves crimes and mysteries

I read a book in middle school probably around 1984 about a group of children who were trying to solve a mystery in their town. It had to do with them finding and retrieving an old satchel from a stopped up/plugged civil war cannon. They used science and experiments along the way. I believe they heated the barrel to remove the plug and get to the bag. I think the group was comprised of all boys? I appreciate any help!

The Mad Scientists' Club by Bertrand R. Brinley.

That's the book, thank you so much! Excited to introduce my boys to these wonderful stories!