Island vs Model

This issue came up just over a year ago.

My post in Digest 981-1 10/11/04
[w/minor changes]
According to

David C. Knight's "Colonies in Orbit' [1977] Pp. 39,40,41

Island 1 was the sphere
Island 2 was the torus
Island 3 was the cylinder pair

Such that 'models' 1,2,3,& 4
were All 'Island 3's

The 4 'Models' are as follows:

Model 1: -only large enough to be workable.
L = 3300'
D = 700'
Per. of Rotation:21 seconds
Pop=5,000 each cylinder

Model 2:
L = 2 mi
D = 2,100'
Per. of Rotation: [not given]
Pop.= 75,000 each cylinder

Model 3:
L = 6mi
D = 1.25mi
Per. of Rotation:[not given]
Pop.= 1,000,000 each cylinder

Model 4:
L = 20 mi
D = 4 mi
Per. of Rotation:114 seconds
Pop.= 10,000,000 each cylinder,
"although as O'Neill points out
{one quarter to one half that number}
might be a more comfortable figure."

{i.e., as little as 2.5 million as
opposed to the max. of 10 million.}

Also:

"Ideally, O'Neill believes, the economics of
efficient use of materials and other
considerations would tend to limit the size
of a typical colony {cylinder}to about 16 mi.
in length and four mi. in diameter"

RKH