In the late 14th century, the rocket launching tube was combined with the fire lance. This involved three tubes attached to the same staff. As the first rocket tube was fired, a charge was ignited in the leading tube which expelled a blinding lachrymatory powder at the enemy, and finally the second rocket was fired. An illustration of this appears in the "Huolongjing", and a description of its effectiveness in obfuscating the location of the rockets from the enemy is provided. The "Huolongjing" also describes and illustrates two kinds of mounted rocket launchers that fired multiple rockets. There was a cylindrical, basket-work rocket launcher called the "Mr. Facing-both-ways rocket arrow firing basket", as well as an oblong-section, rectangular, box rocket launcher known as the "divine rocket-arrow block". Rockets described in the "Huolongjing" were not all in the shape of standard fire arrows and some had artificial wings attached. An illustration shows that fins were used to increase aerodynamic stability for the flight path of the rocket, which according to Jiao Yu could rise hundreds of feet before landing at the designated enemy target.