The American Journal of Science and ArtsS. Converse, 1863 |
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acetate Alphatypic alumina ammonia animal appears astronomy atmosphere axis beds beryl Birds body carbonate Carboniferous cephalization character chemical Chester county childrenite chlorid coal Coal-measures color computed contains corresponding Crustaceans curve Decapods degradational depth of water determined Devonian distance equation experiments fact feet formation formula fossils genus geological glucina heat hydrastine inches inferior Insecteans Insects iron JOUR Journal light lime limestone long-styled lower Mammals mass mean velocity Megasthenes metals meteoric meteorite method Microsthenes miles mineral Mollusks Myriapods nearly nitric acid Nova Scotia observations obtained olivine oxyd Paleozoic plants plate pollen portion posterior potash present produced Prof quantity remarkable Reptiles river rocks salt sandstone SCI.-SECOND SERIES segments shales silicates Silurian soda soil solution species specimens spectrum star stigmas structure sulphuric acid surface temperature Tetradecapods tion vapor Vertebrates vibrations volume XXXVI
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Página 99 - ... the term atmosphere and the term radiation. It is well known that our atmosphere is mainly composed of the two elements, oxygen and nitrogen. These elementary atoms may be figured as small spheres scattered thickly in the space which immediately surrounds the earth. They constitute about 99£ per cent of the atmosphere.
Página 99 - ... those operations which lie beyond the boundaries of sense, and in which sensible phenomena originate. When we speak of radiation through the atmosphere, we ought to be able to affix definite physical ideas, both to the term atmosphere and the term radiation.
Página 215 - ... primitive rocks.* The question here arises, whether in the absence of organic remains, or of stratigraphical evidence, there exists any means of determining, even approximately, the geological age of a given series of crystalline stratified rocks ; in other words, whether the chemical conditions which have presided over the formation of sedimentary rocks have so far varied in the course of ages, as to impress upon these rocks marked chemical and mineralogical differences.
Página 436 - ... points. The most obvious peculiarity of Welwitschia is, that " it appears to be the only perennial flowering plant which at no period has other vegetative organs than those proper to the embryo itself, — the main axis being represented by the radicle, which becomes a gigantic caulicle, and develops a root from its base and inflorescences from its plumulary end, and the leaves being the two cotyledons in a very highly developed and specialized condition.
Página 225 - ... southern extension. Granitoid gneiss is still associated with these crystalline schists. Gold is not confined to the third series, but is also met with in veins cutting the argillites of Upper Silurian age. The crystalline limestones and ophiolites of eastern Massachusetts, which are probably of this series, resemble those of the Laurentian system ; and the coal beds in that region are, in some parts, changed into graphite. It is to be remarked that the metamorphic strata of the third and fourth...
Página 42 - The fades of the Devonian Flora in America is very similar to that of the same period in Europe, yet the number of identical species does not seem to be so great as in the coal-fields of the two continents. This may be connected with the different geographical conditions in these two periods; but the facts are not yet sufficiently numerous to prove this.
Página 220 - ... and universal alteration of areas of sedimentary rocks, embracing many hundred thousands of square miles. On the other hand, the study of the origin and distribution of mineral springs shows that alkaline waters (whose action in metamorphism I first pointed out, and whose efficient agency Daubree has since so well shown) are confined to certain sedimentary deposits, and to definite stratigraphical horizons ; above and below which saline waters wholly different in character are found impregnating...
Página 435 - ... portion forms a stout taproot, buried in the soil, and branching downwards at the end. From deep grooves in the circumference of the depressed mass two enormous leaves are given off, each six feet long when full grown, one corresponding to each lobe; these are quite flat, linear, very leathery, and split to the base into innumerable thongs that lie curling upon the surface of the soil. Its discoverer describes these...
Página 102 - The sun raises the vapours of the equatorial ocean ; they rise, but for a time a vapour screen spreads above and around them. But the higher they rise, the more they come into the presence of pure space, and when, by their levity, they have penetrated the...
Página 100 - Three or four years ago, however, it was found by the speaker that this small modicum of aqueous vapour intercepted fifteen times the quantity of heat stopped by the whole of the air in which it was diffused. It was afterwards found that the dry air then experimented with was not perfectly pure, and that the purer the air became, the more it approached the character of a vacuum, and the greater, by comparison, became the action of the aqueous vapour.