74 LIVING LIGHTS. 



" If during winter one walks along the beach on the snow, 

 which at ebb is dry, but at flood-tide is more or less 

 drenched through with sea-water, there rises at every step 

 an exceedingly intense beautiful bluish-white flash of light, 

 which in the spectroscope gives a one colored labrador-blue 

 spectrum. This beautiful flash of light arises from the snow, 

 that shows no luminosity before it is stepped upon. The 

 flash lasts only a few moments, but is so intense that it 

 appears as if a sea of fire would open at every step a man 

 takes. It produces, indeed, a peculiar impression on dark 

 and stormy winter days. The temperature of the air is 

 sometimes in the neighborhood of freezing of mercury. It 

 is certainly a strange experience to walk along in this 

 mixture of snow and flame, which -at every step one takes 

 splashes about in all directions, shining with a light so 

 intense that one is ready to fear that his shoes or clothes 

 will take fire. If carefully examined, the cause of this 

 phenomenon is found to be a little crustacean, Metridea 

 armata, that somewhat resembles the Cyclops. The great 

 changes of temperature to which it is subjected in the snow- 

 sludge seem not to affect it." 



Few phosphorescent animals exhibit their glories during 

 the day ; but Sapphirina (Plate X., Fig. 6) is an exception. 

 It is one of the largest of the Entomostracans, about a quarter 

 of an inch in length, broad and flat, without the beauty of 

 form which characterizes Cyclops, Calanus, and others ; but 

 what it lacks in this respect is more than compensated by 

 its marvellous powers of light production, few animals of 

 any kind equalling it. So vivid is the phosphorescence, that 

 it can be distinctly seen by day ; and, peering down into the 

 depths where it abounds, flashes of color blue, gold, sap- 



