COLOUR. 65 their axes in the planes of polarization of the light of the squares in which they are respectively seen. When a pleochromatic crystal is placed before L, at the dis tance of distinct vision, and the Ilaidinger’s prism turned round its axis till its planes of polarization coincide with those of the crystal, the two images of the square opening will show the colours of the oppositely polarized pencils of which the trans mitted light is composed. COLOUR. ,, ^0. Colours and their varieties, as arranged by Werner for ^.imrpose of being applied to the description of minerals, are Metallic colours. 1- Pinchbeck-brown. Yellowish-brown, with a metallic lustre. 2. Copper-red. The colour of metallic copper. 3 - -Bronze-yellow. The colour of bronze. 4- Brass-yellow. The colour of ordinary brass. 6. Gold-yellow. The colour of pure gold. 6. Bilver-whitc. The colour of pure silver. • im-white. The colour of pure tin or antimony. P ea( hgrey. The colour of pure lead. 1 “teel-grey. The colour of steel on a recent fracture. ■ iron-black. A blackish grey. Mon-metallic colours. 1- Snow-white. The purest white. 2. -Reddish-white. White inclining to red. 3. Yellowish-white. White inclining to yellow. * *■ Greyish-white. Pure white, with a tinge of grey arising from the transluconcy of the substance in which it occurs. 6 - Greenish-white. White inclining to greenish-grey. 0- Milk-white. The colour of skimmed milk. !• Blueish-grey. Grey inclining to blackish-blue. 2 - Pearl-grey. Grey mixed with red and blue. 3- Smoke-grey. Brownish-grey, the colour of thick smoke. 4 - Greenish-grey. Grey mixed with blackish-green. 5 ' Yellowish-grey. Grey mixed with yellowish-brown. 6. Ash-grey. The purest grey, a mixture of black and white. l • Greyish-black. Black inclining to ash-grey. 2- Yelvet-blaek. The purest deep black. 3. Greenish-black. Black somewhat inclining to green. 4. Brownish-black. Black with yellowish-brown. 6- Blueish-bluck. Black mixed with blue.
