The American Journal of Science, Volumes 167-168J.D. & E.S. Dana, 1904 |
Conteúdo
| 1 | |
| 23 | |
| 34 | |
| 41 | |
| 49 | |
| 79 | |
| 85 | |
| 93 | |
| 365 | |
| 377 | |
| 381 | |
| 392 | |
| 405 | |
| 411 | |
| 423 | |
| 437 | |
| 112 | |
| 133 | |
| 141 | |
| 160 | |
| 171 | |
| 184 | |
| 185 | |
| 191 | |
| 198 | |
| 215 | |
| 234 | |
| 241 | |
| 247 | |
| 253 | |
| 269 | |
| 277 | |
| 301 | |
| 318 | |
| 324 | |
| 331 | |
| 347 | |
| 359 | |
| 459 | |
| 466 | |
| 474 | |
| 483 | |
| 97 | |
| 104 | |
| 113 | |
| 135 | |
| 141 | |
| 147 | |
| 157 | |
| 163 | |
| 165 | |
| 175 | |
| 183 | |
| 197 | |
| 213 | |
| 228 | |
| 237 | |
| 243 | |
Outras edições - Ver todos
Termos e frases comuns
acid activity angle appears axis beds border brachiopods Bryozoa buds calcite carapace Carboniferous cent character chemical Clinton color containing Cretaceous crystals curve cusp deposits described determined Devonian diameter distinct dorsal emanation endodermis evidence experiments fauna feet Fenestella FIGURE formation fossil Fusulina geanticline genera genus Geol Geological gneiss heat hydrogen chloride indicated JOUR Journal later lava layers length limestone liquid lower margin measured method millerite mineral molars Museum nearly nepheline observed obtained occur Ordovician origin Osteopygis ovipositor oxide Paleozoic paper Pelé perigynium plastron plates portion posterior premolar present probably Professor pronotum quartzite radiation radio-active radium region represented rhizome rocks roots salt schists SCI.-FOURTH SERIES seedlings seen shell shown side Silurian similar solution species specimen stage Stegomus structure surface temperature thickness tion tube upper valve ventral width wing wire
Passagens mais conhecidas
Página 415 - ... tendencies due to old age; so that nearly every stage passed through by the higher genera has a fixed representative in a lower genus. Moreover, the lower genera are not merely equivalent to or in exact parallelism with the early stages of the higher, but they express a permanent type of structure, as far as these genera are concerned, and after reaching maturity do not show a tendency to attain higher phases of development, but thicken the shell and cardinal process, absorb the deltidial plates,...
Página 145 - ... form will be found to stand the final test, it may be provisionally accepted as best in accord with our knowledge of the facts at this time. These three hypotheses are : 1. That the rocks of both the eastern and western areas are of the same age, and that they have been bent into a broad synclinal whose flanks are so sharply folded, faulted and thrust as to simulate the fan-structure observed in high mountain chains; and that the eastern flank of this synclinal or fan was much more highly metamorphosed...
Página 288 - Spectroscopic observations made during the condensation of the gas in the charcoal showed the gradual disappearance of the characteristic spectrum of oxygen, nitrogen and air, as the high vacuum was reached and the discharge passed with great difficulty. In tubes of this kind filled at atmospheric pressure...
Página 196 - ... held in place by a platinum wire passing through the foil and tucked under the rubber stopper where the funnel tube enters. The second hole of the stopper is filled by the exit tube, a glass tube of 0.7 cm. internal diameter. This tube is expanded just above the stopper to a small bulb, which serves to prevent mechanical loss of the solid contents of the flask during the boiling, and is joined by means of a rubber connector (provided with a screw pinch-cock) to the inlet tube of the absorption...
Página 296 - ... ordinary temperature. A few experiments have been made using, instead of air, special mixtures of oxygen and nitrogen. Thus it was found that a gas containing 6-5 per cent, of oxygen, used in the same manner as in the air occlusion experiments, gave, on heating up the charcoal rapidly to 15° C., 5 litres of gas having the composition of 23 per cent, of oxygen. A repetition of the same process with the 23 per cent, of oxygen would have raised the percentage about 60 per cent., or a stronger concentration...
Página 420 - Studies in Evolution. Being mainly Reprints of Occasional Papers selected from the Publications of the Laboratory of Invertebrate Paleontology, Peabody Museum. By CHARLES EMERSON BEECHER, Ph.D., Professor of Historical Geology.
Página 238 - ... deep grooves. The shell was therefore composed of tubes or syphons, placed parallel to each other, and revolving laterally, as in the genus melonis of Lamarck, with which its characters undoubtedly correspond. But as in the transverse fracture, its spiral system of tubes cannot be traced to the centre in any of the numerous specimens we have examined, it would seem to have a solid axis, and consequently belongs to that division of the genus that Montfort regards as distinct, under the name of...
Página 25 - Exposed for a few minutes to radium bromide with a radio-active strength of 300,000 and 1,800,000 (uranium being taken as unity), the mineral becomes wonderfully phosphorescent, the glow continuing persistently after the removal of the source of excitation. The bromide was confined in glass. Six hundred grams of kunzite crystals were thus excited with 127 milligrams of the radium bromide in five minutes. The effect is not produced instantaneously but is cumulative, and after a few moments' exposure...
Página 474 - In the summary, Table VII, the compressibilities of English flint glass and of the glass of which ordinary German tubing is made as well as that of mercury have been included for purposes of comparison. The compressibility of mercury rests upon a large number of observations made in the " Challenger,"* by which its apparent cubic compressibility was found to be 1'5 per million per atmosphere.
Página 272 - ... specimens of the rock. In the specimen analyzed about 5 per cent was found. In other specimens more is found, although in no case is it very abundant. It is clear and colourless, but is at once distinguished from the nepheline when examined between crossed nicols by its much higher polarization colours, which in thin sections frequently rise to a blue of the second order. It is clear and free from interpositions, and in convergent light is seen to be uniaxial and negative. It also shows a slight...