Geological Gossip: Or, Stray Chapters on Earth and Ocean

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Routledge, Warne, and Routledge, 1860 - 325 páginas
 

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Página 151 - In looking at Nature, it is most necessary to keep the foregoing considerations always in mind — never to forget that every single organic being around us may be said to be striving to the utmost to increase in numbers; that each lives by a struggle at some period of its life; that heavy destruction inevitably falls either on the young or old, during each generation or at recurrent intervals. Lighten any check, mitigate the destruction ever so little, and the number of the species will almost instantaneously...
Página 162 - Owing to this struggle for life, any variation, however slight, and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to its physical conditions of life, will tend to the preservation of that individual, and will generally be inherited by its offspring.
Página 169 - A grain in the balance may determine which individuals shall live and which shall die, — which variety or species shall increase in number, and which shall decrease, or finally become extinct.
Página 151 - The face of Nature may be compared to a yielding surface, with ten thousand sharp wedges packed close together and driven inwards by incessant blows, sometimes one wedge being struck, and then another with greater force.
Página 160 - Not one man in a thousand has accuracy of eye and judgment sufficient to become an eminent breeder. If gifted with these qualities, and he studies his subject for years, and devotes his lifetime to it with indomitable perseverance, he will succeed, and may make great improvements ; il he wants any of these qualities, he will assuredly fail.
Página 211 - ... to be struck by other bodies in the same movement." This is a somewhat vague hypothesis, not supported by experiment or observation ; but whatever its value may be as regards them, the more artificial forms already found, however few in comparison, are amply sufficient to destroy the value of the doubt as affecting the general question. With regard to the more highly finished of those described by Mr. Evans, they show a uniformity of shape, a correctness of outline, and a sharpness about the...
Página 160 - If selection consisted merely in separating some very distinct variety, and breeding from it, the principle would be so obvious as hardly to be worth notice ; but its importance consists in the great effect produced by the accumulation in one direction, during successive generations, of differences absolutely inappreciable by an uneducated eye — differences which I for one have vainly attempted to appreciate.
Página 132 - Another account in the same volume, by Pietro Jacobeo di Toledo, describing the same fact, adds, — " Some of the stones were larger than an ox. They were thrown up, the larger ones, about a cross-bow's shot in height from the opening, and then fell down, some on the edge of the mouth, some back into it. The mud ejected (ashes mixed with water) was at first very liquid, then less so, and in such quantities that, with the help of the aforementioned stones, a mountain was raised a thousand paces in...
Página 197 - The bottom of the cave, on first removing the mud, was found to be strewed all over, like a dog-kennel, from one end to the other, with hundreds of teeth and bones, or, rather, broken and splintered fragments of bones, of all the animals above enumerated ; they were found in greatest quantity near its mouth, simply because its area in this part was most capacious ; those of the larger animals, Elephant, Rhinoceros, &c., were found co-extensively with all the rest, even in the inmost and smallest...
Página 205 - ... which in shape they resemble, 3. Oval or almond-shaped implements, from two to nine inches in length, and with a cutting edge all round. They have generally one end more sharply curved than the other, and occasionally even pointed, and were possibly used...

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