A letter written by Charles Darwin to a man named Francis McDermot on the subject of God and the Bible is up for auction at Bonhams.

The lot is among the highlights of an auction of science and technology memorabilia on September 21, with an estimate of $70,000-90,000.

Darwin replied honestly to McDermot's question

McDermot had written to Darwin in November 1880 to explain that "...if I am to have pleasure in reading your books I must feel that at the end I shall not have lost my faith in the New Testament.

"My reason in writing to you therefore is to ask you to give me a Yes or No to the question Do you believe in the New Testament.

"If you could answer me Yes I should most gladly enter upon the study of your wonderful books but without that assurance I fear my brain is not fine enough to argue out doubts which might be suggested by your works but if I can say that the author of these doctrines believes as I do that Christ was the Son of God, I can say it is only in matters of detail that Mr Darwin differs from Charles Kingsley and I may read with full pleasure of all the wonders of nature which he has collected."

McDermot then promises not to reveal Darwin's answer to anyone else.

Darwin responds: "Dear Sir, I am sorry to have to inform you that I do not believe in the Bible as a divine revelation & therefore not in Jesus Christ as the son of God."

The content of the letter, a rare example of Darwin making his feelings on religion clear, is likely to ensure strong bidding at auction.

Another Darwin letter, discussing reproduction among barnacles, sold for $25,000 last year, suggesting the estimate for the current lot could be conservative.

The sale will also feature an Apple-1 computer and George Minot's 1934 Nobel Prize in Medicine.

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