Complex sentence: Tesla also thought the system could be used to "transmit intelligible messages to great distances" and thought the layer he energized would "illuminate upper strata of the air" providing nighttime lighting for people below.
Split into simpler sentences: Tesla also thought the system could be used to "transmit intelligible messages to great distances". He also thought the layer he energized would "illuminate upper strata of the air" providing nighttime lighting for people below.