ABOUT two miles above Ormeim, in the Romsdal (Norway) is the well-known Slettafos, an imposing cascade formed by the impetuous Rauma, which here lunges through a deep rocky ravine. Fascinated by the ...

Add Yahoo as a preferred source to see more of our stories on Google. You can see them positioned opposite one another on the color wheel above. Note that there are various color models, on top of RYB ...

IN connection with this subject, which was referred to in Mr. Terrill's letter in NATURE for May 17, perhaps the following homely way of illustrating the fact that the combination of two complementary ...