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425 페이지 - Lavergne, undertaken by desire of the Academy of Moral and Political Sciences of the Institute of France...
473 페이지 - I was surprised by finding how large a number of insects were caught by the leaves of the •common sun-dew (Drosera rotundifolia) on a heath in Sussex.
472 페이지 - Insects" appeared in 1862, thus forming the second volume of the whole series; and the two volumes "On the Effects of Cross- and Self-Fertilization in the Vegetable Kingdom," and "The Different Forms of Flowers on Plants of the same Species...
255 페이지 - Acad. XVI. 364). Very perfect definition would not be required, since it would affect all the stars equally. To an amateur who would regard the complexity of an instrument as a serious objection to it, a means is now afforded of easily reducing his estimates of magnitude to an absolute system, and thus rendering them of real value.
478 페이지 - The proof of this great generalization, like that of all other generalizations, lies mainly in the fact that the evidence in its favor is continually augmenting, while that against it is continually diminishing, as the progress of science reveals to us more and more of the workings of the universe.
30 페이지 - Add to the sulphuric acid one part of the water and cool the mixture. Then dissolve the potassium bromide in six parts of the water by means of heat, supplying the loss of water by evaporation during the heating. Pour the diluted sulphuric acid slowly into the hot solution with constant stirring, and set the mixture aside for twenty-four hours, that the sulphate of potassium may crystallize.
51 페이지 - IT and iri denote the heat — measured in dynamical equivalents — absorbed and evolved at the hot and cold junctions respectively in unit time by unit current. Let E be the electromotive force of a battery, maintaining a current / in such a direction as to cause absorption of heat at the hot junction. Then if R be the whole resistance of the circuit, we have by Joule's law and the first law of thermodynamics : — £!+*!— ^!=11!*. (1) Supposing the whole energy of the current wasted in heat....
259 페이지 - There cannot be more than four layers in the wings and scales, which show principally such colors in insects, two external ones belonging to the cuticula, and two internal ones belonging to the hypodermis. The naked wings of Diptera and Neuroptera often show beautiful interference colors. The scales of Entimus and other Curculionidae are well known for their brilliancy, and it is interesting to remark that when dry scales are examined with the microscope, many are found partly injured, which give...
183 페이지 - ... and comparatively stable characters to the species as we find them in their native haunts. I am not very confident of the success of my prolonged endeavors to put these genera into proper order and to fix the nomenclature of the older species; and in certain groups absolute or practical definition of the species by written characters or descriptions is beyond my powers.