First point...
I will leave the maths to others who can convert the litres to cubic inches
and PSI etc.
Second point...
If I recall correctly Keely's sphere was 14 cubic inches volume. If I still
recall correctly, the volume of a sphere is 4/3 pi r**3 making the sphere
only 1.5 inches in radius or 3 inches in diameter. That sounds rather
small, so it makes me a bit suspicious of the figures quoted in the book.
But it would be easier to build one that size to hold the huge presures. (I
thought it was closer to 110,000 psi)
Third...
I think the use of a sphere by Keely was intentional. He mentions the place
of sympathetic resonance as being at the one third position, or something.
I'll have to go back and read it, but I have the distinct impression that
the shape of the container was important. (i.e a sphere) so a non-spherical
substitute may cause difficulties. (what is, and what shape is, a c.n.g.tank?)
Cheers,
Ted Gallop