The American Journal of Science and ArtsS. Converse, 1860 |
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Página 6
... equal differences , and no two countries present all the varieties of a species common to both , nor are the species of any two countries alike in number and kind . 2. The rate at which plants vary is always slow , and the ex- tent or ...
... equal differences , and no two countries present all the varieties of a species common to both , nor are the species of any two countries alike in number and kind . 2. The rate at which plants vary is always slow , and the ex- tent or ...
Página 19
... equal continental area possesses , and the relative numbers of species to genera ( or other higher groups ) is also much less than in similar continental areas . The further an island is from a continent , the smaller is its flora ...
... equal continental area possesses , and the relative numbers of species to genera ( or other higher groups ) is also much less than in similar continental areas . The further an island is from a continent , the smaller is its flora ...
Página 38
... equal to 4'50 . According to Mr. Schott's latest investigation of the secular change of the decli- nation in Philadelphia supported by observations between the years 1701 and 18557 , the annual increase between the years 1840 to 1845 is ...
... equal to 4'50 . According to Mr. Schott's latest investigation of the secular change of the decli- nation in Philadelphia supported by observations between the years 1701 and 18557 , the annual increase between the years 1840 to 1845 is ...
Página 39
... equal in amount , occur in February and June ( the first one in January at Toronto ) . The ratios of the number of monthly disturbances to the aver- age number are given in the following table , showing the same also divided into ...
... equal in amount , occur in February and June ( the first one in January at Toronto ) . The ratios of the number of monthly disturbances to the aver- age number are given in the following table , showing the same also divided into ...
Página 42
... equals 46 " . From 3 in the morning till 5 in the afternoon , the mean effect of the disturbances is to deflect the north end of the magnet to the west , and during the remaining hours ( principally night hours ) to the east . The ...
... equals 46 " . From 3 in the morning till 5 in the afternoon , the mean effect of the disturbances is to deflect the north end of the magnet to the west , and during the remaining hours ( principally night hours ) to the east . The ...
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Términos y frases comunes
acid American ammonia animals antimony appears arsenic atomic weight aurora Australia beds bismuth carbon carbonic acid Carboniferous character chemical chlorid coast color containing Cretaceous crystals Dép described determine Dicotyledons direction dolomite equivalent existing fact flame flora fluorine formation formula fossil genera genus geographical geological gives gypsum horizon inches iridium iron Journal jurassic known lake less light lignite limestone magnetic mass matter metals meteor miles mineral mountains natural nearly northern observations obtained occur organic orthoclase osmium oxyd oxygen paper pectolite peculiar Permian phenomena phosphorus pieces plants plates platinum portion potash present Prof radials ratio relations remarkable river rocks ruthenium salt scientific SECOND SERIES Sept silica soda solution southern species specimens strata substance supposed surface temperature Tertiary theory tion upper variation varieties vegetation volume whole XXIX
Pasajes populares
Página 148 - As all the living forms of life are the lineal descendants of those which lived long before the Cambrian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world. Hence we may look with some confidence to a secure future of great length. And as natural selection works solely by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection.
Página 147 - Judging from the past, we may safely infer that not one living species will transmit its unaltered likeness to a distant futurity. And of the species now living very few will transmit progeny of any kind to a far distant futurity...
Página 148 - I believe that animals have descended from at most only four or five progenitors, and plants from an equal or lesser number.
Página 158 - The limbs divided into great branches, and these into lesser and lesser branches, were themselves once, when the tree was small, budding twigs; and this connexion of the former and present buds by ramifying branches may well represent the classification of all extinct and living species in groups subordinate to groups.
Página 172 - When we travel southward and see a species decreasing in numbers, we may feel sure that the cause lies quite as much in other species being favored as in this one being hurt.
Página 170 - We behold the face of nature bright with gladness, we often see superabundance of food; we do not see, or we forget, that the birds which are idly singing round us mostly live on insects or seeds, and are thus constantly destroying life ; or we forget how largely these songsters, or their eggs, or their nestlings, are destroyed by birds and beasts of prey...
Página 170 - Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult — at least I have found it so — than constantly to bear this conclusion in mind.
Página 159 - ... extinct and living species in groups subordinate to groups. Of the many twigs which flourished when the tree was a mere bush, only two or three, now grown into great branches, yet survive and bear the other branches ; so with the species which lived during long-past geological periods, very few have left living and modified descendants.
Página 449 - THE BOYDEN PREMIUM URIAH A. BOYDEN, ESQ., of Boston, Mass., has deposited with THE FRANKLIN INSTITUTE the sum of one thousand dollars, to be awarded as a premium to "Any resident of North America who shall determine by experiment whether all rays of light,* and other physical rays, are or are not transmitted with the same velocity.
Página 158 - At each period of growth all the growing twigs have tried to branch out on all sides, and to overtop and kill the surrounding twigs and branches, in the same manner as species and groups of species have at all times overmastered other species in the great battle for life.