so 
Now act upon this with V (which will not affect either 2 
or e) and afterwards take the vector and scalar parts, thus : 
V (Yer + 2e 2 ? — 2eSer) = V a — V 2 -? 
or 2e = 4e 2 = Va - V 2 P 
2e = Yv« and 4e 2 = V 2 P-Sva (3) 
The first of these equations gives the required condition ; 
if the forces acting are conservative Yva=0, and e must be 
constant in direction and magnitude —the magnitude and 
pressure being connected by the second equation. The case 
here considered is the general case of the possibility of a 
quantity of dead water accompanying a moving solid, and 
includes that of fluids in relative rest upon or within the 
earth. 
Considering the possibility of a fluid interior of the earth, 
it must be observed that, owing to precession and nutation, 
the axis of the earth is not constant in direction, and that 
therefore the condition is not truly satisfied. If however 
the shape of the earth gives a stable form for the fluid, the 
viscosity of the fluid will tend to mitigate any departure 
from the apparent rigidity, after such motion has once been 
established. 
Precession must also prevent the absolute rest of fluid 
contained in a vessel upon the earth’s surface, and it is pos- 
sible, though highly improbable, that in this way precession 
might be demonstrated, as Foucault’s pendulum demon- 
strates the earth’s rotation. 
“Did Pascal invent the Wheelbarrow?” by William 
E. A. Axon, M.R.S.L. 
The recent celebrations in honour of Pascal brought up 
once more a curious claim that has been advanced on his 
behalf as the inventor of the wheelbarrow. The statement 
has been made by Jules Janin and other writers, but the 
assertion is purely traditional and has no historic basis. 
