History of floatation

While working at the National Institute of Mental Health (NIMH) in Bethesda, Maryland, Dr Lilly and his colleague Dr Jay Shirley became interested in the origins of conscious activity within the brain.

They wanted to know if the brain needed external stimuli to keep its conscious states active. So, they began devising a system that would restrict environmental stimulation as much as possible.

In Dr Lilly's first tank, the floater was suspended upright and completely submerged, with their head covered by an underwater breathing apparatus and mask.

Over the years, Dr Lilly continued his floatation experiments, simplifying and improving the tank's general design. He found that he could float in a more relaxing lying-down position if he used salt water (which is more buoyant).

In time, he added other improvements such as:

• water heaters with thermostats to keep the water at a perfect temperature
• an air pump to keep the air in the tank fresh
• a water filter for re-using the Epsom salts.

By the early 1970s, Dr Lilly had perfected his floatation tank. The design was largely the same as that of modern-day float tanks.