Què opinen els usuaris - Escriviu una ressenya
No hem trobat cap ressenya als llocs habituals.
Altres edicions - Mostra-ho tot
angle animal appears atom Aurora Borealis Barlow basalt bodies botany carbonic carbonic acid cavities centre colour common contains crystals decomposed dense fluid diameter direction distance Edinburgh effect electric elevation equal expansible fluid experiments extremity feet flame force granite greywacke heat height hyaenas inches intensity iron island Journal July June lava leaf-stalk Lepidolite light magnetic mass mean temp mean temperature memoir mercury metal mineral molecules month motion mountains muriatic acid nature nearly needle nitric acid observations obtained oxide paper pass Perihelion phenomena Pholades phosphoric acid pitchpipe plants plate pole position potash present produced Prussian blue quantity rain remarkable retina right ascension river rocks seen side similar slate snow species specimen substance sulphate sulphuric acid sunrise surface thermometer tion tube ture vapour vibrations volcanic wind wire
Pàgina 81 - This red ray appears to possess a definite refrangibility, and to be characteristic of the salts of potash, as the yellow ray is of the salts of soda, although, from its feeble illuminating power, it is only to be detected with a prism. If this should be admitted, I would further suggest, that whenever the prism shows a homogeneous ray of any colour to exist in a flame, this ray indicates the formation or the presence of a definite chemical compound.
Pàgina 189 - Oil," and besides is subject to such tremendous explosions of gas, as to force out all the water, and afford nothing but gas for several days, that they make but little or no salt. Nevertheless the petroleum affords considerable profit, and is beginning to be in demand for lamps, in workshops and manufactories. It affords a clear, brisk light when burnt this way, and will be a valuable article for lighting the street lamps in the future cities of Ohio.
Pàgina 376 - This last bed of lava must have been brought to a state of the most perfect liquefaction, as it had filled up every crevice that was more than half an inch wide. It appeared highly glazed, and in some places we could discover small round pebbles from the size of a hazel nut to that of a hen's egg, of the same colour, and having the same...
Pàgina 80 - ... presence of the substance, which suffers no diminution in consequence. Thus a particle of muriate of lime on the wick of a spirit-lamp will produce a quantity of red and green rays for a whole evening without being itself
Pàgina 81 - The flame of sulphur and nitre contains a red ray which appears to me of a remarkable nature. This red ray appears to possess a definite refrangibility, and to be characteristic of the salts of potash, as the yellow ray is of the salts of soda, although, from its feeble illuminating power, it is only to be detected with a prism.
Pàgina 81 - If this opinion should be correct, and applicable to the other definite rays, a glance at the prismatic spectrum of a flame may show it to contain substances which it would otherwise require a laborious chemical analysis to detect.
Pàgina 277 - The travellers reached the elevation of 15,500 feet, where the pass appeared to be 1,400 or 1,500 feet higher, over vast fields of snow. The dell is broad (half a mile wide), and covered with snow in high wreaths. The mountains, which have a SE exposure, are nearly bare, a few patches of snow only appearing at great heights. The line of cliffs may be 17,500 feet. On the other side, the mountains are nearly of the same height, and they present a chain of mural precipices, eaten away by frost into...
Pàgina 189 - There is a continual discharge of carbonated hydrogen gas from the well ; and also from the bed of the creek on which the well is situated, at various places for the distance of half a mile. This gas is highly inflammable, and where there is a free discharge of it...
Pàgina 272 - ... black head; all else was a dreary solitude of unfathomable snow, aching to the sight, and without trace of a path. " The travellers found the snow, which was soft at mid-day, afford good footing, and reached the summit with less fatigue than they anticipated. They remained the night and following day at the crest of the pass, and suffered much from head-ache and difficulty of breathing, usually experienced at such elevated positions. It snowed in the evening. The temperature did not rise above...
Pàgina 158 - Very few aeriform explosions seem to have taken place, since scarcely any scoriae were ejected, and the few that occur lie in beds upon the surface of the lava, around its three principal sources, and were therefore thrown up after its emission. At each of these points is a very small cone. The most easterly, called the Fackerkohl, has an evident crater encircled by rocks of basalt covered by scoria?.