1972 52 989 The speed of sound in Baker DB-grade castor oil has been measured at temperatures between 0° and 40°C and pressures between atmospheric and 110MPa (megapascals).
1990 P. Kearey & F. J. Vine ii. 19 Pressure increases with depth at a rate of about 30 MPa km−1, mainly due to the lithostatic confining pressure of the overlying rock.