Photo of 2003 - Leonard Hill, the first to test proper decompression in the middle with 2 divers

Leonard Erskine Hill theorized and tested the first continuous decompression

Around 1900, Leonard Erskine Hill theorized that recompression could be used to treat decompression sickness and slow decompression would prevent compressed air illnesses. He wrote the first slow continuous decompression tables. He used this method to compress himself and Major Greenwood to a pressure of around 6 atmospheres and successfully decompressed themselves by allowing 20 minutes at every atmosphere as the pressure was being lowered.