(1) _Effects._ At very close (point-blank) range almost all of the burning fuel can be fired at great velocity directly through ports and openings into the target. Maximum casualties and damage are caused in the hostile position. (2) _Protection._ Common sense precautions are taken to prevent casualties to friendly personnel from possible ricochet or rebounding of flame. If the target includes a vertical wall at a right angle to the firer or other friendly personnel, the weapon should not be fired at closer than 7 to 10 yards. When the weapon is fired at small openings in a bunker or pillbox, the firer and other members of the assault squad should not approach closer than 7 to 10 yards from the target. _b. Other effective ranges._ (1) _Open fields of fire._ When thickened gasoline is used, portable flame throwers may fire with considerable effect as far as 40 yards under normal conditions, depending on wind direction and wind speed. Under the same conditions, liquid fuel maybe effective at 20 yards. Results and accuracy are not as great as at point-blank range. (2) _Jungle or thick underbrush._ If the target is located in jungle or thick underbrush without cleared fields of fire, the effective range of the flame thrower is reduced by as much as one half, depending on the nature and density of the vegetation. _c. Ineffective ranges._ Although the flame may reach considerably farther than the ranges stated in _b_ (1) above it may be useless because of the steep angle of descent and because much of the fuel is burned before it reaches the target. 23. WIND DEFLECTION. Wind is an important factor because of the low velocity of the flaming fuel. Wind can lengthen, shorten, or deflect the flame. _a. Head winds._ Head winds of more than 5 miles per hour tend to carry heat or even flame back toward the firer. Liquid fuel should not be fired into a head wind of more than 5 miles per hour. The range and accuracy of thickened fuels is reduced. _b. Following winds or very light winds._ Best results are obtained under these conditions. _c. Cross winds._ When firing at or near maximum range, cross winds deflect, breakup, and disperse the flame. They also reduce the range. 24. FIRING POSITIONS. _a. Ease of aiming._ The flame thrower can be fired from any position that permits sufficient freedom to aim the weapon, subject to the conditions in _b_, _c_, and _d_, below. This includes standing, kneeling, and prone. In some instances, flame throwers have been fired with tank groups resting on the ground or on skids. If used in this way, the tops of the fuel tanks must be propped up to conform to _b_, below. _b. Angles of the tanks._ When firing, the bottoms of the fuel tanks must always be substantially lower than the tops. The tops of both tanks must also each be the same distance above the horizontal and neither tank should be tilted to one side. Otherwise, only a small part of the fuel may be blown from the tanks.