CONCENTRATING THE FIRE OF A GROUP OF GUNS, ETC. 
313 
To meet this case draw out a diagram for No. 1 gun as before 
described, cl beiug the distance of No. 2 from No. 1 ; then draw on the 
diagram a second arc outside the first, graduate it, and number it so 
that the reading at the point where the line joining the centres of the 
correction circles cuts this arc corresponds with the reading on No. 3 
gun arc when its line of fire is at right angles to the line joining 2 and 
3. A reference to fig. 4 will make the meaning clear. 
The Group Officer to ascertain the corrections lays the scale first over 
the training ordered, on the inner arc, notes the correction and gives 
it out to No. 1 gun ; then swings the scale over to the same training 
on the outer arc, and gives the correction thus found to No. 3. If the 
distance of No. 3 from No. 2 is not the same as that of No. 1, the 
graduations on its deflection bar must be proportionately reduced as 
before described. 
