=Heavy Field Howitzer.= No type of heavy field howitzer developed during the war has given general satisfaction. The consensus of all army artillery officers—French, English and American—is that two calibers of howitzers are necessary—one a companion piece for the 6” gun and one of the maximum possible power consistent with the necessary mobility. The lighter of these two howitzers should have the same mobility as the 6” gun, with a caliber of about 8” and a maximum range of not less than 16,000 yards. The heavy field howitzer should be of about 9.5” caliber with a range in excess of 16,000 yards; the carriage should provide for wide traverse and must have sufficient mobility to accompany the army in the field. It will probably be necessary to transport this howitzer in more than one load, and the maximum weight of any load should not exceed 12 tons. The average time necessary for occupying a position should not exceed six hours under actual field conditions. =Heavy Field Howitzer. Ideal.= A caliber of about 8” on a carriage permitting a vertical arc of fire of from 0 to plus 65 degrees; and a horizontal arc of fire of 360 degrees. The maximum range should be 18,000 yards. =Heavy Field Howitzer. Practical.= Use at present 8” material of British design which is on hand. =Railway Artillery.= The war has demonstrated the necessity for long range and powerful guns for distant interdiction and harassing work and for super-heavy howitzers for the destruction of semi-permanent fortifications. Artillery of these types can best be mounted on railway carriages and this type of mount offers no serious disadvantages since these guns will not be used except with large forces which require extensive railroad systems for their supply. This does not apply to guns of the type used to bombard Paris; such guns have no military value and their construction is not justifiable. ANTI-AIRCRAFT GUNS. =Light Gun. Ideal.= Caliber about 3” with initial velocity of at least 2,600 f. s.; semi-automatic breechblock, mounted on carriage, permitting 80 degrees elevation and 360 degrees traverse; projectiles weighing not less than 15 pounds, of one type high explosive shell with maximum ballistic qualities and as large explosive charge as possible; fixed ammunition; smokeless, flashless powder, mechanical fuse. In this type every effort must be made to increase the rate of fire and decrease time of flight; this latter is limited only by considerations of a reasonable accuracy life for the gun. =Light Gun. Practical.= Arm units with present 3” anti-aircraft equipment. Continue experiments leading to the development of the ideal. =Transport. Ideal.= Caterpillar mount or caterpillar trailer mount drawn by caterpillar tractor, each unit to permit a sustained speed of 12 miles per hour. CHAPTER V THE 3-INCH FIELD GUN. THE GUN.