Uncertain Blue -green at www.japanese-home-gardens.com

Because Clerk Maxwell added red, green, and blue light together, this technique is called additive. An equal addition of the three colors forms white; red and green add to form yellow; red and blue, magenta; green and blue, the blue-green known by photographers as cyan. It is important to bear in mind that this theory holds true only for colored light; the mixture of pigments is another matter.

Near the main Geysir are other hot springs, blow-holes, and boiling mud-baths. One of the hot springs is shaped like a pair of spectacles, each "lens" of cart wheel size, and is therefore called Gleraugnahver. One of its lenses is of an uncertain blue -green blue-green color, the other is of the very bluest blue you will ever see, and it retains its phenomenal azure iridescence even on cloudy days.

Sao Miguel calls itself "The Green Island" in tourist folders but its fabulous hydrangea highways, thick hedges with blue blossoms lining the roads on both sides mile after mile, make it a blue-green island for two or three months from about July 1. I have never seen anything in my travels at all like these island roads. They resemble green tunnels through luxuriant shade trees arching overhead, with a blue and white "dado" on either side.