then he raised one foot and drove the heavy heel of his cowboy boot down on the hollow orange , striking it so forcefully that the dried husk cracked with a boom as loud as a small bomb ; an infant screamed itself awake at the sound of the explosion , and its mother shot an angry glance through the branches into the trees interior though she was unable to see us ; glossy chestnut horses pulling a wagon past the sour orange , pricked their ears and tossed their heads ; a snare drummer paused at the unexpected thump in the middle of his roll ; we were stunned by the sound for a moment and then we gasped , and what was better , we cheered to see a small yellow curl of pulverized orange smoke rise up from under the boys boot like little tendrils of a fern .