14 May 2001:  John Lahr's calculated flat-earth minus spherical-earth
residuals for three focal depths: 0, 100, 150 km.  He used Hypoellipse
for all calculations.  The results differ from mine (using other programs)
by at most 0.01 km/s.

Focal Depth = 0 km

 F-S    Distance
 0.00	0.0    
 0.00	50.0  
 0.00	100.0 
 0.10	150.0
 0.11	200.0  
 0.15	250.0   
 0.18	300.0 
 0.21	350.0  
 0.25	400.0  
 0.29	450.0  
 0.32	500.0  
 0.37	550.0  
 0.41	600.0  
 0.45	650.0  
 0.49	700.0  
 0.53	750.0  
 0.58	800.0  
 0.63	850.0  
 0.68	900.0  
 0.72 	950.0  
 0.77	1000.0 
 0.83	1050.0 
 0.89	1100.0 
 0.95	1150.0 
 1.01	1200.0 
 1.07	1250.0 

Focal Depth = 100 km

 F-S    Distance
 0.00	0.0   
 0.04	50.0  
 0.08	100.0 
 0.15	150.0 
 0.21	200.0 
 0.26	250.0 
 0.33	300.0 
 0.43	350.0 
 0.49	400.0 
 0.56	450.0 
 0.63	500.0 
 0.70	550.0 
 0.77	600.0 
 0.84	650.0 
 0.92	700.0 
 0.99	750.0 
 1.07	800.0 
 1.14	850.0 
 1.24	900.0 
 1.32	950.0 
 1.41	1000.0
 1.50	1050.0
 1.58	1100.0
 1.68	1150.0
 1.76	1200.0
 1.90	1250.0 

Focal Depth = 150 km

 F-S    Distance
 0.00	0.0   
 0.03	50.0  
 0.09	100.0 
 0.18	150.0 
 0.27	200.0 
 0.33	250.0 
 0.45	300.0 
 0.57	350.0 
 0.65	400.0 
 0.76	450.0 
 0.85	500.0 
 0.95	550.0 
 1.07	600.0 
 1.17	650.0 
 1.28	700.0 
 1.41	750.0 
 1.53	800.0 
 1.65	850.0 
 1.80	900.0 
 1.95	950.0 
 2.12	1000.0
 2.29	1050.0
 2.45	1100.0
 2.64	1150.0
 2.84	1200.0
 3.07	1250.0