Cheaper by the Dozen

them.
    There was still some wall space left, and Dad had more than enough ideas to fill it. He tacked up a piece of cross-section graph paper, which was a thousand lines long and j a thousand lines wide, and thus contained exactly a million little squares.
    "You hear people talk a lot about a million," he said, "but not many people have ever seen exactly a million things at the same time. If a man has a million dollars, he has exactly as many dollars as there are little squares on that chart."
    "Do you have a million dollars, Daddy?" Bill asked.
    "No," said Dad a little ruefully. "I have a million children, instead. Somewhere along the line, a man has to choose between the two."
    He painted diagrams in the dining room showing the difference between meters and feet, kilograms and pounds, liters and quarts. And he painted seventeen mysterious-looking symbols, representing each of the Therbligs, on a wall near the front door.
    The Therbligs were discovered, or maybe a better word would be diagnosed, by Dad and Mother. Everybody has seventeen of them, they said, and the Therbligs can be used in such a way as to make life difficult or easy for their possessor.
    A lazy man, Dad believed, always makes the best use of his Therbligs because he is too indolent to waste motions. Whenever Dad started to do a new motion study project at a factory, he'd always begin by announcing he wanted to photograph the motions of the laziest man on the job.
    "The kind of fellow I want," he'd say, "is the fellow who is so lazy he won't even scratch himself. You must have one of those around some place. Every factory has them."
    Dad named the Therbligs for himself—Gilbreth spelled backwards, with a slight variation. They were the basic theorems of his business and resulted indirectly in such things as foot levers to open garbage cans, special chairs for factory workers, redesign of typewriters, and some aspects of the assembly line technique.
    Using Therbligs, Dad had shown Regal Shoe Company clerks how they could take a customer's shoe off in seven seconds, and put it back on again and lace it up in twenty-two seconds.
    Actually, a Therblig is a unit of motion or thought. Suppose a man goes into the bathroom to shave. We'll assume that his face is all lathered and he is ready to pick up his razor. He knows where the razor is, but first he must locate it with his eye. That is "search," the first Therblig. His eye finds it and comes to rest—that's "find," the second Therblig. Third comes "select," the process of sliding the razor prior to the fourth Therblig, "grasp." Fifth is "transport loaded," bringing the razor up to the face, and sixth is "position," getting the razor set on the face. There are eleven other Therbligs—the last one is "think!"
    When Dad made a motion study, he broke down each operation into a Therblig, and then tried to reduce the time taken to perform each Therblig. Perhaps certain parts to be assembled could be painted red and others green, so as to reduce the time required for "search" and "find." Perhaps the parts could be moved closer to the object being assembled, so as to reduce the time required for "transport loaded."
    Every Therblig had its own symbol, and once they were painted on the wall Dad had us apply them to our household chores—bedmaking, dishwashing, sweeping, and dusting.
    Meanwhile, The Shoe and the lighthouses had become a stop on some of the Nantucket sightseeing tours. The stop didn't entail getting out of the carriages or, later, the buses. But we'd hear the drivers giving lurid and inaccurate accounts of the history of the place and the family which inhabited it. Some individuals occasionally would come up to the door and ask if they could peek in, and if the house was presentable we'd usually show them around.
    Then, unexpectedly, the names of strangers started appearing in a guest book which we kept in the front room. "Are these friends of yours?" Dad asked Mother.
    "I never heard of them before. Maybe they're friends of the children."
    When we said we didn't know them, Dad questioned Tom Grieves, who admitted readily enough that he had been showing tourists through the house and lighthouses, while we were at the beach. Tom's tour included the dormitories; Mother's and Dad's room, where the baby stayed; and even the lavatory, where he pointed out the code alphabet. Some of the visitors, seeing the guest book on the table, thought they were supposed to sign. Tom stood at the front door as