[Unit = Length of Semi-major Axis. 
48 
The N.Z. Journal of Science and Technology. [Feb. 
If a = 0, e — 1, and SA = 0, which is evident, since the impact is 
now direct. 
If in any case the ratio of k : K is known we can determine the 
constant c and draw graphs giving the values of e and a ( 1 — e) for all 
angles of projection. 
