The tick escaped from Tom, presently, and crossed the equator. Joe harassed him awhile, and then he got away and crossed back again. This change of base occurred often. While one boy was worrying the tick with absorbing interest, the other would look on with interest as strong, the two heads bowed together over the slate, and the two souls dead to all things else. At last luck seemed to settle and abide with Joe. The tick tried this, that, and the other course, and got as excited and as anxious as the boys themselves, but time and again just as he would have victory in his very grasp, so to speak, and Tom's fingers would be twitching to begin, Joe's pin would deftly head him off, and keep possession. At last Tom could stand it no longer. The temptation was too strong. So he reached out and lent a hand with his pin. Joe was angry in a moment.