Last Tuesday, as the Senate passed the homeland security bill, two staffers were several floors below, poking around amid the mice and the dust in a Capitol subbasement.

Surely the intrepid staffers must have known that it's always in obscure, creepy spaces where fantastic discoveries are made.

And hadn't construction workers told the staffers, Clare Amoruso and Douglas Connolly, that anything not removed from this subterranean warren by Thursday would be dumped and lost forever? Great saves are always made in the nick of time.

Yeah, right.

Anyway, after seeing two mice, and after securing files of the Senate Democratic Policy Committee, for which they work, Amoruso and Connolly ventured into one mysterious chamber just to explore. Curiosity got the better of them.

The floor was poured concrete. Boxes were stacked everywhere. The staffers opened the boxes and found . . . thousands of blank health care forms.

To the dump.

Then they noticed some books strewn carelessly on a metal shelf. One in particular caught their attention. It was very old and bound in canvas for better preservation. The pages of faded ink were handwritten by people who must have lived at a time when penmanship mattered.

Some of the names were familiar.

Amoruso and Connolly turned more pages.

Wait, the familiar men seemed to have actually signed these pages!

They looked at the title of the volume, stamped in gold on the spine:

"Senators Compensation and Mileage."

Yeah, right.

"1790-1881."

Within minutes, Senate Historian Richard Baker was examining the find. And yesterday, outgoing Senate Majority Leader Tom Daschle (D-S.D.) was displaying the volume to reporters while archivists wearing white gloves turned the pages for the cameras. Also on display were 59 additional books with records through the mid-1950s that were found in the same underground room.

The first volume is probably the only document with the signatures of John Adams, Thomas Jefferson and Aaron Burr, not to mention subsequent Senate luminaries like John C. Calhoun. All were vice presidents and, therefore, presidents of the Senate. So all had to sign requisitions for senators' pay and mileage reimbursements.

"It is, literally, priceless," Daschle said. "It came within a whisker of being totally destroyed."

The chamber of forgotten health care forms and one priceless book lies beneath the Capitol's East Front steps. The subbasement warren will be demolished to make way for construction of the Capitol Visitors Center.

"It was an 'Oh my God' kind of moment," Amoruso recalled. "I said, 'Doug, this must be a transcribed copy, it can't be the original.' "

"Nobody writes 'Thomas Jefferson' like Thomas Jefferson," Connolly said.

A volume on compensation and mileage wouldn't say much in most cases. But when the institution in question is a bureaucracy as self-important and practical as the Senate, it is a glimpse into its soul.

Senators treated minutiae of remuneration seriously. They still do. Same with voters -- then and now.

Senators started out making $6 a day for every day they were in session. They got 30 cents a mile for the commute to and from their home states. When the ledger was begun, Congress still met in Philadelphia.

Those were the days when travel featured bouncing until your false teeth fell out. Senators couldn't claim more than 20 miles per day, or a maximum of another $6. Aaron Burr was paid $28.50 for the 95-mile trip from New York to Philadelphia. James Gunn was reimbursed $284.10 for the 947-mile journey from Georgia. In 1837-38, when pay had risen to $8 a day and travel to 40 cents a mile, Daniel Webster was paid $1,944 for 193 days in session and the 1,000 miles from Massachusetts.

Today senators receive $150,000 ($166,700 for the two leaders and the president pro tem). A vestige of the old mileage system survived until 1995. Now travel expenses come out of Senate office budgets that range from $2.1 million to $3.5 million. Senators receive as much as $165 a day for food and lodging on official trips.

Most of the ledger's pages feature columns of names and figures, but Baker, the historian, can decode a narrative behind the numbers, beginning with the Senate as "a mom-and-pop organization" of 28 members (from the 13 Colonies and Kentucky).

"This book starts with the country hugging the Eastern Seaboard, and when it's through, there are 76 senators across the land mass of the continent," Baker says. "It's a great metaphor for the growth of the nation, to say nothing of the growth of the Senate."

In 1816, senators were tired of being paid by the day and voted to give themselves an annual salary of more than $1,000. Voters were incensed, many incumbents were defeated, and in the next session the daily rate was restored -- but fattened from $6 to $8. Annual salaries did not take hold until about 1855.

In the early 1830s, when President Andrew Jackson fought Congress over the banking system, the Senate presented the ledger to the Treasury Department for reimbursement. Several years in a row, Treasury officials added the same snippy note in neat handwriting to the ledger, accusing the Senate of drawing more than its share. Baker noted the executive branch's "passive-aggressive" thrust at the legislative branch -- a style that has never gone out of fashion in Washington.

In 1881, the space in the 400-page ledger was all used up. In 1884, the secretary of the Senate realized the book was special and had it re-bound. It was deposited in the National Archives.

In 1963, the Senate's disbursing officer ordered all 60 compensation ledgers sent from the Archives, and he apparently used the oldest volume as a desk reference. It wound up in the subbasement, forgotten.

In about six months, the book will be scanned and posted on the Senate's Web site; eventually it will go on display in the Capitol Visitors Center.

After conjuring up nearly a century of Senate history yesterday, Daschle took questions.

What do you think of the Saudi ambassador's wife giving money that could have reached terrorists?

Back to work as a senator in 2002.

Senators have something to look forward to when they return in 2003: raises. Up to $154,700, $171,900 for the leaders.

A page from the 1790-1881 volume, dated April 3, 1790, bears the signature of John Adams, then vice president.Sen. Tom Daschle, left, and Senate Historian Richard Baker with some of the 60 ledgers, including the volume that covers 1790 to 1881.