“20000 Leagues Under the Sea” Part1 Ch21

Question 1:

“Are they apes?” cried Ned Land. “Very nearly – they are savages.”

Man is often differentiated from animal by his powers of reasoning and intelligence.  Yet among men, we speak of certain peoples as being more advanced or civilized than others.  What does it mean to be civilized?  Can an uncivilized or less advanced people be taught so that they advance to the level of understanding and adeptness at using advanced technology of their teachers?  Can such be accomplished in a single generation or might it require several generations to advance a previously “backwards” people?

Question 2:

Shells are all right-handed with rare exceptions; and, when by chance their spiral is left, amateurs are ready to pay their weight in gold.

Are left-handed shells really such a rarity?  Why are so many right-handed and so few left-handed?  Why does nature prefer right-handed shells over left-handed ones?

Answer 2: According to www.jaxshells.org, most gastropod species normally produce right-handed shells, although a few species normally produce left-handed shells.  The scientific term for right-handed shells is “dextral”, while the scientific term for left-handed shells is “sinistral”.  There are rare cases however where a sinistral specimen of a normally dextral species will be found. Likewise there are rare cases of where a dextral specimen of a normally sinistral species is found.

see http://www.jaxshells.org/stuff.htm for more information.

Question 3: Was Dumont d’Urville a real sailor, a “Captain Cook” of the Frenchmen as Captain Nemo claimed?

Question 4: The natives trying to enter the Nautilus were shocked by electricity conducted by the staircase cable rail.  How are modern electric fences effective yet nonlethal to cattle?

Question 5 – The rising tide lifted the Nautilus off the coral it had been stuck on for days.  In the oceans what are the average fluctuations in sea level due to the tides, i.e. how much higher is the ocean at high tide versus low tide?

Answer 5: pg. 194 of Volume 19 of the “Academic American Encyclopedia”, Copyright 1983, published by Grolier Incorporated says:

In the deep ocean the tidal range rarely exceeds 0.5 m (1.6 ft), but in shallow coastal waters the tidal range increases, just as surf grows when it approaches a beach.  The effect is reinforced in bays and estuaries whose natural period of oscillation is close to the tidal period.  Tides in the Bay of Fundy, for example, have a range of 13.6 m (44.6 ft). 

Question 6: Professor Aronnax found a shell of the species “Oliva porphyria Linnaeus” of the genus olive, class of gastropods on the Island of Gilboa in the South Pacific.  Where is this species usually found?

Answer 6: According to the book “Shells” by S. Peter Dance (Copyright 2002, published by Dorling Kindersley Inc., New York, N.Y.):

They are usually found from the Gulf of California to Panama off the West American shore.  Otherwise known as the “Tent Olive” due to its tent like markings formed as the result of pigments secreted by this animalat the edge of its outer lip as it grows.

For pictures of this shell, see http://www.jaxshells.org/1129no.htm

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