I am currently writing about the "de Morgan's laws" and have seen both "de Morgan" and "De Morgan."
Which of these is correct?
I am currently writing about the "de Morgan's laws" and have seen both "de Morgan" and "De Morgan."
Which of these is correct?
I believe I know where the occasional lower case spelling (and thus your confusion) comes from.
Take for example this book which contains "Selected papers from the 7th Augustus de Morgan Workshop, London". Note the lower case "de".
The editors of the book were Dutch (Amsterdam University Press, Johan van Benthem); and in Dutch, words like "de" or "van" are spelled with a lower case when used in the middle of a person's name, and capitalized when used at the beginning. So a Dutch person, even when writing about an Englishman, would be tempted to write "His biography tells us that De Morgan was born in India" (capital D to indicate the use of "De" as the start of a name) but "Augustus de Morgan entered Trinity College when he was sixteen" (lower case "de" in the middle of a name).
I suspect that other sources of the use of "de" can similarly be traced to authors whose culture would naturally use lowercase in the middle of the name; but if you want to get it "right" you should spell the name the way he did - which is "Augustus De Morgan", as @fdb's answer demonstrates.
People have the right to choose how they spell their own names. The person in question spelled his name as "De Morgan", e.g. here (on page vi):
Why not consult the "History of Mathematics Archive" at http://www-groups.dcs.st-and.ac.uk/~history/index.html ? It contains mini-biographies of hundreds of mathematicians.