translation.en: Well, it turns out that Einstein and Kaluza and many others worked on trying to refine this framework and apply it to the physics of the universe as was understood at the time, and, in detail, it didn't work.
translation.zh: 其实，“爱因斯坦”，“卡鲁扎”以及其他 致力于优化这个体系 并试图将其应用于当时被认知到的宇宙物理学， 发现在细微处该理论并不能反应现状。