The archivists requested a donkey, but what they got from the mayor’s office were four w

ary black sheep,which, as of Wednesday morning, were chewing away at a lumpy field of grass beside the municipal archives building as the City of Paris’s newest, shaggiest lawn mowers. Mayor Bertrand Delano has made the environment a priority since his election in 2001, with popular bike- and car-sharing programs, an expanded network of designated lanes for bicycles and buses, and an enormous project to pedestrianize the banks along much of the Seine.

The sheep, which are to mow (and, not inconsequentially, fertilize) an airy half-acre patch in the 19th District intended in the same spirit. City Hall refers to the project as “eco-grazing,” and it notes that the four ewes will prevent the use of noisy, gas-guzzling mowers and cut down on the use of herbicides. Paris has plans for a slightly larger eco-grazing project not far from the archives building, assuming all goes well; similar projects have been under way in smaller towns in the region in recent years.

The sheep, from a rare, diminutive Breton breed called Ouessant, stand just about two feet high. Chosen for their hardiness, city officials said, they will pasture here until October inside a three-foot-high, yellow electrified fence.

“This is really not a one-shot deal,” insisted René Dutrey, the adjunct mayor for the environment and sustainable development. Mr. Dutrey, a fast-talking man in orange-striped Adidas Samba sneakers, noted that the sheep had cost the city a total of just about $335, though no further economic projections have been drawn up for the time being.

A metal fence surrounds the grounds of the archives, and a security guard stands watch at the gate, so there is little risk that local predators — large, unleashed dogs, for instance — will be able to reach the ewes.

Curious humans, however, are encouraged to visit the sheep, and perhaps the archives, too. The eco-grazing project began as an initiative to attract the public to the archives, and informational panels have been put in place to explain what, exactly, the sheep are doing here.

“Myself, I wanted a donkey,” said Agnès Masson, the director of the archives, an ultramodern 1990 edifice built of concrete and glass. Sheep, it was decided, would be more appropriate.

But the archivists have had to be trained to care for the animals. In the unlikely event that a ewe should flip onto her back, Ms. Masson said, someone must rush to put her back on her feet.

Norman Joseph Woodland was born in Atlantic City on Sept. 6, 1921. As a Boy Scout he learned Morse code, the spark that would ignite his invention.

After spending World War II on the Manhattan Project , Mr. Woodland resumed his studies at the Drexel Institute of Technology in Philadelphia (it is now Drexel University), earning a bachelor’s degree in 1947.

As an undergraduate, Mr. Woodland perfected a system for delivering elevator music efficiently. He planned to pursue the project commercially, but his father, who had come of age in “Boardwalk Empire”-era Atlantic City, forbade it: elevator music, he said, was controlled by the mob, and no son of his was going to come within spitting distance.

The younger Mr. Woodland returned to Drexel for a master’s degree. In 1948, a local supermarket executive visited the campus, where he implored a dean to develop an efficient means of encoding product data. The dean demurred, but Mr. Silver, a fellow graduate student who overheard their conversation, was intrigued. He conscripted Mr. Woodland.

An early idea of theirs, which involved printing product information in fluorescent ink and reading it with ultraviolet light, proved unworkable.

But Mr. Woodland, convinced that a solution was close at hand, quit graduate school to devote himself to the problem. He holed up at his grandparents’ home in Miami Beach, where he spent the winter of 1948-49 in a chair in the sand, thinking.

To represent information visually, he realized, he would need a code. The only code he knew was the one he had learned in the Boy Scouts.

What would happen, Mr. Woodland wondered one day, if Morse code, with its elegant simplicity and limitless combinatorial potential, were adapted graphically？ He began trailing his fingers idly through the sand.

“What I’m going to tell you sounds like a fairy tale,” Mr. Woodland told Smithsonian magazine in 1999. “I poked my four fingers into the sand and for whatever reason — I didn’t know — I pulled my hand toward me and drew four lines. I said: ‘Golly! Now I have four lines, and they could be wide lines and narrow lines instead of dots and dashes.’”

Today, bar codes appears on the surface of almost every product of contemporary life.All because a bright young man, his mind ablaze with dots and dashes, one day raked his fingers through the sand.