Answer: "It says "International Correspondence Schools" which still exists.Probably a course on chemicals?Now, be careful. Chemical regulations in the 20's were not the same as now. Based on your pictures, you could have nasty toxic chemicals that can go through a glove and kill you (the mercury vial), explosive degradation products (ammonium) and other surprises like that. Earth near from them could be contaminated too.I suggest you do not linger near from them. Perhaps you can arrange a meeting with a university chemical lab and know more about the set, including safe disposal options."