Boart Longyear wireline core retrieval system, an innovation that revolutionized the diamond drilling industry by increasing productivity on the worksite and making tripping core from the bottom of the hole safer for the drilling assistant. Later named the Q Wireline System, the new core retrieval method introduced a level of productivity never before seen in the exploration drilling industry. In 1964 Longyear sold 25 percent of its family-owned stock to FACTS, a Luxembourg-based holding company owned jointly by Boart International and Christensen Diamond Products Company. Three years later FACTS exercised its option to purchase another 25 percent of Longyear's family stock. The
Léon Teisserenc de Bort an indication of a temperature inversion or at least of a zero lapse rate above this altitude. For many years he was uncertain whether he discovered a true physical phenomenon or whether his measurements suffered from a systematic bias (indeed, the first measurements "did" have a positive temperature bias as the instruments were liable to radiative heating by solar radiation). That is why Teisserenc de Bort carried out 200+ more balloon experiments (with a substantial part of them being held during the night to eliminate radiative heating) until 1902, when he suggested that the atmosphere was divided into two layers.