The fluid layer thus discovered has the following characteristics.
The fluid layer adheres to the entire surface of solids and liquids. Its thickness is roughly half a mm and it defies gravitation owing to the strong surface potential. The fluid film is like a smooth sheet on a smooth surface and uneven on a rugged surface.Its density is roughly midway between a gas/air and a liquid under normal atmospheric conditions.
It is compressible but offers resistance to compression. Material in the fluid layer does not overflow from the surface when heated, however it expands. Temperate and pressure influence the fringes in the fluid layer. When two glass plates are pressed together their respective fluid layers merge under pressure and a complex fluid is formed like a sheet of liquid with broad fringes. When the pressure is eased and the plates are separated, the fluid layers on the respective surfaces are restored as in the original state. This indicates that every point on the surface has a potential to hold particular thickness fluid layer at a given temperature and pressure and the original state is restored once the change in these parameters is reversed.
Hence the fluid layer seen in normal atmospheric conditions is a combination of fluid films of various gases. With the combination of fluid layers of two surfaces either solid Vs. solid, solid Vs. liquid, liquid Vs. liquid, a 'complex fluid' is formed which takes a definite shape depending on the shape of the surfaces brought together.
Both the isotopes of liquid Helium i.e. He3 and He4 give rise to their own fluid films on the surfaces of the container when the temperature is increased just above their critical liquefaction temperature. This is generally known as Superfluidity of liquid Helium.
When the solid surface like a glass plate is kept vertically in a chamber with high vacuum and if temperature is reduced gradually fluid film of each gas gets withdrawn from the surface of the glass plate at the liquefaction temperature of the respective gas. Slowly Oxygen, Nitrogen and Hydrogen fluid films get withdrawn leaving only fluid films of the esotopes of Helium 3 and Helium 4. At 2.17 K Helium 4 film will be withdrawn and at 0.02 K. Helium 3 film will be withdrawn from the surface. Further with the disappearance of fluid film on the solid surface at near absolute zero as discussed above, the density ripples (diffraction pattern) and the possibility of forming 'complex fluid' also disappears. Hence it is predicted that no Newton's rings nor any fringe pattern can be seen under these conditions.
In the discharge tube experiment studying the cathode rays at 10 KV and 0.1 mm pressure, the cathode glow was seen moving away from the cathode giving rise to the Crook's dark space between the cathode and cathode glow. This can be explained as the fluid layer attached to the cathode captures the electrons and gives add to the glow. As more electrons are captured in the fluid layer, due to repulsion between the cathode and the negative charge built up in the fluid layer, the fluid layer gets detached and moves forward forming the Crook's dark space. As more electrons are captured the fluid layer gets dissipated gradually due to repulsions of the electrons with-in the fluid layer.