322 THE POPULAR SCIENCE MONTHLY. 



who paid much, more attention to the butterflies of the tropical 

 seas than to those of the nearer Mediterranean, pronounced them 

 nocturnal high-sea animals. They had never been seen near the 

 coast, nor before sunset. They were not found at a less distance 

 than about ten marine miles from the coast, and disappeared in 

 the deep at daybreak. That may be correct for the tropical re- 

 gions, where a dazzling sunlight is poured upon the highly heated 

 surface of the sea ; but it must not be forgotten that the sea-but- 

 terflies have no eyes, and their keeping away from the coast, 

 where the water is highly warmed to a considerable depth, may 

 indicate that temperature is more a determining factor in this 

 behavior than light. The sea-butterflies behave differently in the 

 Mediterranean. They are not wanting on sunny days, but are 

 more numerous when the sky is clouded and in the night. In 

 midsummer they are, like many other pelagic animals, extremely 

 rare, and keep themselves in the great deeps. Prof. Chun, of 

 Konigsberg, who investigated this matter in the summer of 1886, 

 fished larvae of Cymbulia and Tiedemannia from as great depths 

 as a thousand metres. Temperature may also be the decisive 

 moment in this case; why should the animals not spend their 

 summer vacation there ? The sea-butterflies of the Mediterranean 

 are not at all afraid of the coast. The Bay of Villafranca is 

 hardly two kilometres wide, and they swim in the straits and 

 harbor of Messina. I have caught multitudes of needle-butterflies 

 in the daytime in that stream, close by the shore. 



The case is somewhat different in the polar seas. We hunt 

 the whale during the polar summer, when the sun does not set 

 for months, and not in the polar nights, which are also months 

 long, and when the ships would be frozen in the ice. If the Cli- 

 ones and Limacinas were night animals they would not come to 

 the surface during the whaling season, and would also not be 

 known to sailors and hunters. They might, in fact, seek the deep 

 in winter for the same reasons that they resort to it in summer in 

 the Mediterranean — to escape extremes of temperature. Every- 

 thing that lives depends on external conditions, and, as these are 

 not everywhere the same, the behavior of the organisms subject 

 to them must adapt itself to the local relations. — Translated for 

 the Popular Science Monthly from Land und Meer. 



The fact that the enforcement of the legal requirements as to air-space in 

 school-rooms fails of itself to secure a wholesome atmosphere, has been empha- 

 sized by Dr. George Eeid's inspections of the schools of Stafford, England, where 

 from 2-039 to 3-708 volumes of carbonic acid per 1,000 volumes of air were found 

 to be present. With all the air that may be allowed, arrangements for some kind 

 of circulation are still necessary. 



