Projectile of 13 pounds, caliber 3”. Projectile of 26 pounds, caliber 4”. Projectile of 52 pounds, caliber 5”. Projectile of 104 pounds, caliber 6”. Projectile of 208 pounds, caliber 8”. Projectile of 416 pounds, caliber 10”. Projectile of 832 pounds, caliber 12”. Projectile of 1664 pounds, caliber 14”. The second and more logical method, and one followed in our service, is to consider the artillery missions and determine the types best suited irrespective of any theoretical series of weights and calibers. However, in the discussion of artillery missions and the proper types for their fulfillment there is a remarkable degree of unanimity of thought on these subjects; and the above table actually contains, with slight variations, the types that are most strongly recommended. While granting the great variety of artillery missions that often shade into each other, it is believed that they can best be considered in three great classes that follow the tactical composition of a field army: those of division, corps and army artillery. DIVISION ARTILLERY. =Missions.= The division artillery, first of all, must have the mobility that will permit it to accompany the infantry of a division and the maximum power consistent with that mobility; its object must be primarily the infantry of the opposing division. It is therefore bound to its own infantry with the closest bonds and its tactical use cannot be separated from that of the infantry. The division artillery must fire, accurately, a man killing projectile and be prepared for quick changes of targets; it must have a great range because of depth, both of its own and the enemy division; it must continually harass the enemy, prevent his movement and force him into cover or protected trenches. On the defensive it must break up the opposing infantry formations by preparing a counter-offensive fire and by annihilating fire on points from which the enemy attacks emerge; and, failing in these, be prepared to use the barrage and shrapnel fire at close range. In the offensive the division artillery must play its part in the complex schemes of artillery preparation by cutting wire, destroying machine gun nests, gassing areas, concentrating on infantry positions and taking the principal part in the deep barrage that should precede the infantry attack. Its fire, accompanying the infantry movement, requires its own movement and by its mobility it often becomes for some time the sole artillery protection in the preparation and holding of a position which has been taken.