Complex sentence: Tesla performed pioneering experiments in short-range wireless power transmission beginning in 1891 and, after further research at a laboratory in Colorado Springs from 1899 to 1900, became convinced that long-range power transmission was possible.
Split into simpler sentences: Tesla performed pioneering experiments in short-range wireless power transmission beginning in 1891. During further research at a laboratory in Colorado Springs from 1899 to 1900, he became convinced that long-range power transmission was possible.