The Truman Doctrine arose from a speech delivered by President Truman before a joint session of Congress on March 12, 1947.
Positive First. When installing a mower battery, always connect the positive cable first. The positive cable is red. It attaches to the battery terminal post marked with a plus sign, the letter P or the word POS. Attach the negative cable last. The negative cable is black.
1 Attach one end of the positive cable clamp to the positive terminal of the dead battery (the positive cable may have a stripe, or if the cables are marked with red and black, the red cable is positive).  Attach the other end of the positive cable to the positive terminal of the good battery.