We'll never know if this stuff worked. Actually, I think the Federal Bureau of Investigation took it down for security purposes, sometime in the early 1900s.
我们也许永远不会知道这能否成功。事实上我认为 依据联邦调查局的调查结果 这个项目基于安全原因被关闭了 这还是在20世纪早期的某些时候