MQ R S Q R 1/2 .500 .600 .400 1.111 .333 .667 1/2 .667 .667 .333 1.333 .500 .500 % 1.000 .750 .250 1.556 .667 .333 % 1.429 .857 .143 1.778 .833 .167 1 2.000 1.000 .000 2.000 1.000 .000 This shows that there is a wide difference in coefficients in the interpolation formulte, and tan sO t hhat the value of — s ould be found be tan w fore using these formulm except in making the corrections in the original ranges, when the value of n may be assumed as indicated for the general class of firings to which it be longs and the coefficients Q , R and S found by interpolation for the value of M under consideration. The corrections may be subse quently recalculated. In correcting the data of firings, corrections for wind are also needed. The correction in feet for a vdnd in the plane of fire is tszi idXn(1- tan o) in which n is the exponent of v in the expres sion W the wind velocity in miles per hour, if it is in the plane of fire; otherwise W is the com ponent of the wind in the plane of fire, and T the time of flight in seconds.
Deflections in degrees due to cross-wind and drift, also in degrees, are given by the formulm 84W j V T cos 9$ I Wind deflection — V cos 01 X Drift d' (1 — (9) i.$) sec 0 in which W is the cross-wind component in miles per hour, K a coefficient having a value 0.75 for direct fire and 0.80 for high angle and curved fire, and the number of calibres that the projectile passes over in making one turn around iti axis due to the action of the rifling.
In the solution of the inverse problem cor rections should first be made for all slight variations in conditions from the mean con ditions existing at the time of the experiments; so that for each group of shots fired the ranges will be reduced to a common value of 0, and the whole series to a common muzzle velocity and ballistic coefficient.