Boart Longyear diamond drilling firm; Brainard-Kilman, a maker of civil engineering devices, such as well monitoring and test equipment; and ChemGrout a mfg of cement grouting equipment. Longyear acquired Slope Indicator Company, the nation's largest producer of geotechnical instruments, and Northern Air Supply in 1988, followed by the Campbell Pacific Division in 1989 and WTD Environmental Drilling in 1990. Then in 1994, North Star Drilling Company, specializing in sonic drilling was acquired. On January 2, 1995, Boart International and the Longyear Company officially merged into a single company and changed its name to Boart Longyear Limited. At this point the two companies
Léon Teisserenc de Bort Léon Teisserenc de Bort Léon Philippe Teisserenc de Bort (5 November 1855 in Paris, France – 2 January 1913 in Cannes, France) was a French meteorologist and a pioneer in the field of aerology. Together with Richard Assmann (1845-1918), he is credited as co-discoverer of the stratosphere, as both men announced their discovery during the same time period in 1902. Teisserenc de Bort pioneered the use of unmanned instrumented balloons and was the first to identify the region in the atmosphere around 8-17 kilometers of height where the lapse rate reaches zero, known today as the tropopause. He was the