![Transactions of the Edinburgh Field Naturalists & Microscopical Society. 1887-88.] Polarised Dark-ground Illumination. j 31 inch in producing the well-known buttons, known originally as Barton s buttons." Sir David Brewster, in Transactions of the Edinburgh Field Naturalists & Microscopical Society. 1887-88.] Polarised Dark-ground Illumination. j 31 inch in producing the well-known buttons, known originally as Barton s buttons." Sir David Brewster, in](https://c8.alamy.com/comp/RMNAAF/transactions-of-the-edinburgh-field-naturalists-amp-microscopical-society-1887-88-polarised-dark-ground-illumination-j-31-inch-in-producing-the-well-known-buttons-known-originally-as-barton-s-buttonsquot-sir-david-brewster-in-experimenting-on-s-eel-lines-found-that-grooves-of-1000-to-the-inch-with-the-light-striking-at-various-angles-gave-as-follows-at-90-white-74-brilliant-blue-60-pink-24-green-while-a-specimen-ruled-to-500-lines-to-the-inch-gave-yellow-through-out-you-will-thus-observe-that-we-have-now-two-factors-iu-the-proposition-namely-1-fineness-or-degree-RMNAAF.jpg)
Transactions of the Edinburgh Field Naturalists & Microscopical Society. 1887-88.] Polarised Dark-ground Illumination. j 31 inch in producing the well-known buttons, known originally as Barton s buttons." Sir David Brewster, in
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