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.

Similarly, the inertia parallel to Oy and Oz is NW' - 1 B W', B C (b2 +-X, c 2 ab and A +C abc/ZP, Ao For a sphere a=b=c, Ao= Bo=Co =, 'a' = Q = = z, (9) U from (II), (16) so that the effective inertia of a sphere is increased by half the weight of liquid displaced; and in **frictionless** air or liquid the sphere, of weight W, will describe a parabola with vertical acceleration W - W', g (30) W+ aW Thus a spherical air bubble, in which W/W' is insensible, will begin to rise in water with acceleration 2g.

Thomson (Lord Kelvin) to form a theory of vortex atoms in a homogeneous, incompressible and **frictionless** liquid."

If this relation is true along all paths, the velocity of the aether must be of irrotational type, like that of **frictionless** fluid.

Artificial membranes are seldom or never perfectly semi-permeable - some leakage of solute nearly always occurs, but the imperfections of actual membranes need no more prevent our use of the ideal conception than the faults of real engines invalidate the theory of ideal thermodynamics founded on the conception of a perfect, reversible, **frictionless**, heat engine.

If the system be subject to **frictionless** constraints, e.g.

The a/~celeration of G is therefore less than in the case of **frictionless** sliding in the ratio a2/(K2+a2).

If we imagine the system reduced by **frictionless** constraints to one degree of freedom, so that the co-ordinates 0, 0, 0,.

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.

Given perfect information, **frictionless** markets, and other theoretical impossibilities, a finite amount of utility can be achieved in that way.

**Frictionless** coatings that never wear out in machines that last for centuries.