An important feature added to the discussion by Adams is the different behaviour of spectral lines 880 860' 840' 820' 800 780' 760 740' 720' 700 0 consider first a frictionless fluid.
Now if this state be supposed established in a frictionless fluid, the con sideration of internal friction would simply extend the char acteristics found at any spot to the neighbourhood, and there fore if the boundary were a sphere and so for a frictionless fluid an exception, it would cease to be an exception when we allow for viscosity.
If the system be subject to frictionless constraints, e.g.
In Thomas Walker's harpoon or frictionless log, introduced in 1861, the wheelwork was enclosed in a cylindrical case of the same diameter as the body of the rotator or fan, and the latter was brought close up to the register, forming a compact machine and avoiding the use of the 6-ft.
Now, whatever be the direction in which a body is moving, a frictionless constraint, like a string attached to the body, can cause its velocity to be changed into the vertical direction without any change taking place in the magnitude of the velocity.
Given perfect information, frictionless markets, and other theoretical impossibilities, a finite amount of utility can be achieved in that way.
If this relation is true along all paths, the velocity of the aether must be of irrotational type, like that of frictionless fluid.
If we imagine the system reduced by frictionless constraints to one degree of freedom, so that the co-ordinates 0, 0, 0,.