Brewster Napier was a man from Lyra's world who wrote, along with Margery Stevenson, a paper called "Some effects of rose oil in polarised light microscopy" which was published in Proceedings of the Microscopical Institute of Leiden. The paper hadn't been noticed by the Magisterium and was published two years before Lyra Silvertongue went on a journey through Asia. Brewster had sandy hair and spoke with a Scottish accent.
Before writing his paper, a technician in Brewster's laboratory had trouble with a microscope which had had a tiny bit of rose oil placed on one of the lens. After investigating it, he asked a friend, Margery, to take a look at it as she was interested in the Rusakov field. They found that the oil allowed them to see various effects of the field and so wanted to make it public knowledge.
They published it with the Microscopical Society of Leiden because it was not a very influential body. After originally no response, they noticed that there labs had been broken into and that they were questioned by people connected with Security or Intelligence.
Around two years following the publishing of the paper, he attended the meeting discussing Anthony Hassall in the Linnaeus Room of the Botanic Garden. Brewster had talked to Anthony during the last time he was in Oxford.