Decompression (diving) but in later experiments signs of what was later to become known as decompression sickness were observed. Later, when technological advances allowed the use of pressurization of mines and caissons to exclude water ingress, miners were observed to present symptoms of what would become known as caisson disease, compressed air illness, the bends, and decompression sickness. Once it was recognized that the symptoms were caused by gas bubbles, and that re-compression could relieve the symptoms, Paul Bert showed in 1878 that decompression sickness is caused by nitrogen bubbles released from tissues and blood during or after decompression, and showed the
Decompression theory of oxygen. This became known as the thermodynamic model. More recently, recreational technical divers developed decompression procedures using deeper stops than required by the decompression tables in use. These led to the RGBM and VPM bubble models. A deep stop was originally an extra stop introduced by divers during ascent, at a greater depth than the deepest stop required by their computer algorithm. There are also computer algorithms that are claimed to use deep stops, but these algorithms and the practice of deep stops have not been adequately validated. A "Pyle stop" is a deep stop named after Richard Pyle,