A remarkable 62-object exhibit about Thomas Jefferson's interest in science -- complete with buffalo robe, mastodon teeth, etc., opened with a reception last night at the National Museum of American History.

It was all put together by Silvio A. Bedini, the Smithsonian Institution scholar in charge of rare books, but who is sometimes greeted as the capital's walking encyclopedia, and whose exhibits (such as the one on Christopher Columbus) have astounded many.

The buffalo robe, not usually considered a scientific instrument, was given to Jefferson upon the return of the Lewis and Clark expedition, and reflects Jefferson's passion for geography and exploration in general. On it are dozens of wild Indians with arrows in their chests and other incidents of tribal warfare, neatly picked out in greens, reds and yellows. No blues. Jefferson was interested in Indian culture and customs, and started collecting Indian vocabularies.

Jefferson's telescopes are to be seen, along with his superb mastodon jaw and fossil mastodon teeth. Bedini, who has been pursuing Jefferson for decades, considers the president's interest in paleontology his most important contribution to American science. It was such a new subject then, and Jefferson did much to make it semi-respectable.

One small example of the Smithsonian's scholarly research may interest viewers of Jefferson's little portable lap desk, designed by Jefferson in 1776 and made by a Philadelphia cabinetmaker. On this he wrote the Declaration of Independence (early drafts of which are still to be seen at the Library of Congress).

This desk passed to Jefferson's heirs who decided, about 1880, to give it to the United States. It went to the Department of State and stayed there until Charles Evans Hughes, looking around him, thought that State had a lot of stuff that belonged elsewhere. So in 1921 the desk was given to the Smithsonian.

But news surfaced, over the years, that the German chancellor, Bismarck, had the sacred relic on which Jefferson wrote the immortal document and something of a hue and cry arose that this priceless republican object should be returned from imperial hands. A newspaper enjoyed a long and yapping crusade about it.

The Smithsonian, which was certain it had the original, was baffled. It turned out, once the question was raised, that a handful of other people, besides Bismarck, arose to say they had the historical desk. How did this happen?

Obviously there were copies, but when and why were they made? Bedini made it one of his minor, but endlessly laborious, tasks to find out. He waded through tons (not to split hairs) of papers of Jefferson descendants, picking up leads, and endless records of congressional investigations for other leads.

For instance, the Treasury Department once looked into charges that a secretary had abused Treasury resources, and in the interminable documents that resulted from this investigation, Bedini found out that Henry Flagg French, an assistant secretary and father of the sulptor, Daniel Chester French, had had 18 copies of the Jefferson desk made, presumably in government workshops. One went to Presendent Rutherford B. Hayes. Others went to other notables. Over the decades these passed to heirs, and perhaps one of them, an admirer of Bismarck, gave the chancellor one of them. (An additional six reproductions were made years later, "very poor ones," Bedini observed, but let it pass).

One thing that had puzzled Bedini was how it happened these replicas of the desk all seemed to have an inscription in Jefferson's own hand attesting to the authenticity of the desk. It turned out they were photographic reproductions of the original inscription on the original desk. At the time they were copied, in the 1880s, a photo process was used that did not involve an emulsion. Hence, tests for photographic minerals salts did not disclose anything. Once the photo process was recognized, it became clear the seemingly original inscriptions of the replicas were merely photographic copies.

Bedini, who likes to keep on pursuing things, wondered how Bismarck got one of the replicas. Bismarck, it turned out, had kept the replica (which he evidently thought was the original) in an iron safe. During World War I, things in that safe were among the few valuable object saved. In correspondence between the Princess von Bismarck and Bedini, that lady assured Bedini her desk was the original. Bedini wrote back there was no doubt of even the least trifling sort about the matter: The Smithsonian desk was the original, and the princess' desk was a replica. The princess took umbrage, Bedini felt, at this plain fact, "and is probably going to sue me" or have him flogged or something.

Which shows the hazards of wholesome innocent scholarly research. Which lies behind object after object now in important museums.

Bedini, as it happens, has not met the princess and, one senses, is not sure he would be safe in her presence.

"She's sending her son over here this summer," he said, possibly with somewhat less than his usual sparkling ebullience. The show will continue until July 4.