The Royal Society is appealing for a "white knight" to buy some notes by the 17th Century scientist Robert Hooke.
The society says the notes will add to knowledge of early modern science
Hooke, who was also an architect and inventor, was one of the original fellows of the Royal Society from 1663.
Notes he made at early meetings of the Royal Society are to be auctioned in London and it hopes a benefactor will come up with the estimated £1m price.
President Lord Rees said the society could not afford them but they would be of "great interest" to researchers.
Their contents have previously been published but Lord Rees said the notes themselves would be useful to those looking at the early history of the Royal Society and its role in the development of modern science.
"It would be wonderful to see these documents purchased by a 'white knight' who would allow them to be made available to researchers," said Lord Rees.
"It is a great pity that the Royal Society cannot itself afford to purchase them so that they could be restored to our collection of documents, from which they were removed at some point during our early history."
Lord Rees said the notes would be a valuable addition to the society's library and archives, which he said contained one of the world's most important collections of manuscripts from the early days of the modern scientific revolution in the 16th and 17th Centuries.
Hooke, who lived from 1635 to 1703, was curator of experiments and then one of two secretaries to the society between 1677 and 1682.
He put forward a wave theory of light, is credited with coining the term "cell" in a biological context and was known in the 17th Century as an inventor and designer of scientific instruments.
He is understood to have feuded with Newton and other scientists of the time and the society says the writings shed light on the disputes.
Auctioneers Bonhams estimate the notes will fetch at least £1m.
After the Great Fire of London, Hooke was appointed surveyor to the City of London and designed many buildings, including the asylum "Bedlam" (the Bethlehem Hospital).
Hooke also worked with Sir Christopher Wren on the Royal Observatory at Greenwich, and The Monument to the great fire.
His friend John Aubrey wrote this about him in his middle years: "He is but of midling stature, something crooked, pale faced, and his face but little below, but his head is lardge, his eie full and popping, and not quick; a grey eie.
"He haz a delicate head of haire, browne, and of an excellent moist curle. He is and ever was temperate and moderate in dyet, etc."