You Xi Wang sat inside the cavern. At this moment, his body was levitating over the lava river flowing inside the cave. He had isolated himself from the world by casting level nine isolation barrier arrays. He had also cast a rune array to dispel the spirit energy inside the barrier.
However to make it so that the energy is not completely dispelled he had cast a level one spirit gathering array at the four directions around himself. This way the energy will be constantly cycling in and out of the barrier at a very low rate. This rate was what he needed to perceive the particle's movements.
The system said, [Master, this setup is truly a genius idea to study the movements in the spirit particles.]