THE VALUE OF A HIGH SITE FOR COAST ARTILLERY. 
231 
used, in the second the 900 yards and so on; it is easily seen that in 
these cases PX is much smaller than PT. 
It will be noticed that at a short range it is almost impossible to 
miss; as shewn by the lines through 300. 
It must be remembered that the heights given in fig. 12 are those 
above the line of sight, so that even if the guns were placed as low 
as considerations of tide would admit of, all ideas of “sweeping a 
channel” are quite delusive, when the objectives are such practically 
horizontal targets as modern torpedo boats. 
