In the physical sciences, Pascal's law or the principle of transmission of fluid-pressure states that "pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same." The law was established by French mathematician Blaise Pascal.

where

is the hydrostatic pressure (given in pascals in the SI system), or the difference in pressure at two points within a fluid column, due to the weight of the fluid;

is the height of fluid above the point of measurement, or the difference in elevation between the two points within the fluid column (in metres in SI).

The intuitive explanation of this formula is that the change in pressure between two elevations is due to the weight of the fluid between the elevations.

Note that the variation with height does not depend on any additional pressures. Therefore Pascal's law can be interpreted as saying that any change in pressure applied at any given point of the fluid is transmitted undiminished throughout the fluid.

Julius Sumner Miller (May 17, 1909 – April 14, 1987) was an American physicist and television personality. He is best known for his work on children's television programs in North America and Australia.

Julius Sumner Miller was born in Billerica, Massachusetts the youngest of nine children. His father was Latvian, his Lithuanian mother spoke 12 languages.

Miller graduated with a Philosophy degree and a Master's in Physics from Boston University in 1933 but due to the Depression worked as a butler for a wealthy Boston doctor for the next two years during which time he married the doctor's maid, Alice Brown; they were to have no children, but he was to go on to reach millions of children through his popular science programs.

After making over 700 applications for employment, in 1937 he was offered a place in the Physics Department of Dillard University, a private, black liberal arts college in New Orleans. During World War II he worked as a civilian physicist for the U.S. Army Signal Corps while holding fellowships in physics at the universities of Idaho and Oklahoma and was a Ford Foundation Fellow at UCLA. In 1950 he enrolled in the Institute for Advanced Studies in Princeton, N.J. where he was a student of Albert Einstein. He became a lifelong friend of Einstein and went on to amass a collection of Einstein memorabilia that included Einstein's birth certificate. Miller also taught at Princeton but disliked large institutions, leaving in 1952 to join the Physics Department at the then small El Camino College in Torrance, California (1952–1974), to maximum student enrollments due to his great popularity and where he was instantly recognizable by his casual hair and horn-rimmed spectacles.