A PERUSAL of the articles which have appeared in your journal on this subject (NATURE, vol. lxxxiii., pp. 48, 68, 188, 487, and vol. lxxxiv., p. 87) leads me to ask if the spectrum of water has ever ...

Add Yahoo as a preferred source to see more of our stories on Google. You perceive electromagnetic radiation in the form of light in all the colors of the rainbow. MirageC/Movement via Getty Images ...

QUESTION: Which animal can see the widest spectrum of colours? Mantis shrimp have remarkable colour vision. They have as many as 16 types of photoreceptor cone, compared with the three humans have.