Washington ? Doodles and drawings done by engineers to guide the manufacture of everyday things sometimes qualify as art, the Smithsonian Institution thinks. As evidence, it has framed 74 of them to send across the country for display in museums.

Many of the artists remain unknown. Their productions in the show range from the 1938 patent drawing for the Maidenform bra to a 1904 project for New York’s Grand Central Terminal.

Two drawings of Grand Central are curator Steven Lubar’s favorites. Carefully tinted and detailed in ink and watercolor, they were drawn nine years before the architectural masterpiece opened to show what its facades should look like.

There’s also an 1891 design for a hydroelectric plant at Niagara Falls, an aluminum tennis racket, a telescoping shopping cart, a goose decoy in a carrying case and an electromechanical fly catcher.

Put together at the National Museum of American History, the show called “Doodles, Drafts and Designs” opens Jan. 31 at Seattle’s Museum of History and Industry, then goes on a three-year tour.

It is expected to be seen in California, Iowa, New York and Texas and to be shown in Washington, D.C., as well, but arrangements are tentative.

Engineers’ drawings also are important to business and social history, Lubar said. Two centuries ago, craftsmen didn’t need drawings much. They learned their crafts, and that knowledge included how to make their products. They were free to produce and improve them as they liked.

A good craftsman could break away from an employer and set up in business for himself with a small investment.

As mass production and automation developed to require many precise drawings, however, so did the relationship between employer and workman. Breaking away became much harder.

“A drawing means, ‘Do it this way, the way I show here,'” Lubar said.

“Compare a musket from the 1770s with a modern rifle. The man who made the musket made each part and fitted them together. Each gun was his own work,” he said. “Today’s rifle is made by many people, each part to exact measurements.”

That doesn’t mean that today’s worker is unskilled, he said; making a piece of a machine from a drawing requires great skill, but a different skill from the old craftsman’s.

One of the exhibits was sketched during a luncheon meeting, on a paper napkin with a ballpoint pen. The designer was Felix Zandman of Malvern, Pa., head of an electronics firm. It’s the first idea for a kind of resistor, widely used to control the current in a circuit.