The old Roman emperor Caligula thought he had a bright idea. By publishing his edicts on stone tablets in a mountaintop temple too high in the clouds for anyone to see, he was free to change his mind whenever he pleased.

It was to prevent federal bureaucrats from turning caliginous with their regulations that President Franklin D. Roosevelt signed legislation 50 years ago today that created the Federal Register.

Obscure, gray and often unintelligible to the general public, the Register is must reading for lawyers and lobbyists. It is the government's official bulletin board, a way for agencies to communicate with their constituent groups, and a chronicle of the ever-changing regulations and executive orders that have become more pertinent -- and more numerous -- than the laws passed by Congress.

Its daily press run of 35,000 copies makes it small by comparison with many newspapers, but its readers are dedicated. It is on the shelves of most Washington law offices, and copies go to all of the government's 1,300 depository libraries across the country.

"It goes to a wide spectrum of people," said John E. Byrne, director of the Register since 1980. "For example, if you're in the livestock business, you've got to follow the Department of Agriculture regulations . . . . It helps people participate in government."

Pre-Register days were far different. Up until the early 1930s, agencies kept their rules in file cabinet drawers, with amendments tacked on in handwritten form. In one celebrated case, government lawyers took a citizen to court for violating a rule that they later discovered -- to their embarrassment -- the agency involved had already repealed.

The idea for an "Official Gazette" of the government really belonged to Edwin N. Griswold, a Washington lawyer who was frustrated with the state of things. In a 1934 article in the Harvard Law Review, Griswold called the existing system "chaos."

"If a pamphlet is discovered which purports to contain the rules and regulations in question," he wrote, "there is no practical means of telling whether the entire regulation or the article in question is still in force, or, as is so often the case, has been modified, amended, suspended or withdrawn."

Asking whether "there is no alternative," he answered himself: "The solution is amazingly simple. All that is needed is an official publication . . . in which all the rules and regulations shall be systematically and uniformly published."

Although the law creating the Register was signed on July 26, 1935, the first edition did not come off the presses until March 1936. A short time later, the Federal Register published the first of its annual compilations of the Code of Federal Regulations.

Griswold, now 81, went on to be dean of Harvard Law School and, from 1967 to 1973, solicitor general of the United States.

Besides chronicling changing regulations, the Register has also provided a mirror of the bureaucratic landscape. Its expansion reflected the expansion of Washington's role in American life, beginning with the New Deal in the '30s and World War II in the '40s.

In 1975 President Gerald R. Ford took note of the bloating of the Register when he said in a speech: "Just to list all of the rates and regulations established last year required 45,000 pages of very small print in the Federal Register."

In 1982, when Reagan administration officials were looking for proof of their success in cutting the size of government, they noted that in President Reagan's first year the Register had 25 percent fewer pages than it had at the end of Jimmy Carter's last year in office.

Byrne noted that the number of pages has continued to decline since then. "There has obviously been a diminution of pages of regulatory material and publication announcements," he said.

In the past, the Register has drawn fire for being incomprehensible to all but those who have mastered inside-the-Beltway bureaucratese. Fred Emery, director of the Register in the 1970s, initiated many changes to try to make it more readable, such as requiring agencies to summarize what they were doing in the first paragraph of their notices.

Still, even the summaries can often read like garbled nonsense to the uninformed, as evidenced by a sample from yesterday's edition. A Food and Drug Administration final rule on animal drugs, feed and "ivermectin injection" reads:

"The Food and Drug Administration FDA is amending the animal drug regulations to reflect approval of a supplemental new animal drug application NADA filed by Merck Sharp and Dohme Research Laboratories providing for safe and effective use of IVOMEC (ivermectin) injection in reindeer for treatment and control of warbles. The regulations are also amended to establish the tolerance and safe concentrations for drug residues in edible reindeer tissues."

But Byrne isn't too concerned. "Sometimes the business about complicated regulations gets out of hand," he said. "I'm a student of English too, but I don't go to the Federal Register for literary things. To be precise sometimes doesn't have the greatest flow. There has been an effort -- it blows hot and cold -- to make government regulations simpler."

The Office of the Federal Register now runs a workshop on document-drafting for federal agencies, and teaches bureaucrats how to keep their notices clear and simple, particularly in the summary and preamble paragraphs.

Asked what the public can expect from the next 50 years of its official Register, Byrne replied, "When the government issues regulations, we'll continue to publish them and get them out to the people."