[Illustration: Relative Numerical Strength of Field Artillery] Let us picture a land fight: Our aërial scouts inform us that the enemy is approaching, and that they have already mounted their long-range field artillery on a convenient ridge; also that they have placed their big howitzers on an adjoining lowland under the concealment of a wood, and that this formation is repeated in similar units from ridge to ridge and hill to hill over a front a hundred miles in length. The enemy has also dug long lines of trenches far in advance of their artillery. The enemy's position is well beyond the range of our artillery. We are unable to reach the enemy's position with our guns, while the enemy, being provided with guns of much longer range, is able to storm our position along our entire front, and to throw shrapnel shell into the trenches filled with our men, which stretch along the lowland in front of our positions. We try to dig additional trenches to advance our front, but the men sent to do the work are very quickly killed by the shrapnel fire of the enemy. We see with our field-glasses that the enemy has sent out detachments to advance the line of their trenches. We fire at them, and find that our shrapnel falls far short. The enemy, seeing this, advances and digs trenches close up to the limit of the range of our guns. All at once, the enemy opens fire with shrapnel upon our entire line of trenches, and with shrapnel and howitzers upon all our fortified positions. We return the fire, but without any effect; the range of our guns being too short to reach the enemy. Many of our guns are quickly silenced. The perfect hurricane of shrapnel thrown upon our trenches has killed large numbers of our men and confounded the remainder. The infantry of the enemy now advances pell-mell over the intervening space, still under cover of artillery fire. Field batteries of the enemy also advance rapidly and take up new positions. Finding our positions untenable, our army retreats precipitately, taking with it a few remaining guns, and our men re-form their batteries on commanding positions to cover our retreat, but they are soon dislodged by the long-range guns of the enemy. Finally, our army takes up its stand far in the rear, forming a new battle-front, which has been previously fortified. The enemy advances, repeats the previous tactics, forming a long battle-front on commanding positions just beyond the range of our guns, and again proceeds to dislodge us, and drive us back by their long-range gun-fire. Our loss in men and guns has been enormous. The enemy, on the contrary, has lost no guns, and but few men. It will be seen that the enemy can very easily proceed in this manner into the interior, and conquer the whole country without suffering very much discomfiture, unless we have guns of as long or longer range than the enemy has, and as many of them, also as many skilled troops to operate them.