A Complete Course of Meteorology

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Página 575 - ... stream of explosions, which died away and re-commenced with the opposite Electricity in equal violence. The stream of fire was too vivid to look at for any length of time, and the effect was most splendid, and continued without intermission, save that occasioned by the interchange of electricities for upwards of five hours, and then ceased totally. During the whole day, and a great part of the succeeding night, there was no material change in the barometer, thermometer, hygrometer, or wind ;...
Página 550 - The unit of solar radiation to be adopted in - the ultimate reduction of the actinometric observations is the actine, by which is understood that intensity of solar radiation, which at a vertical incidence, and supposing it wholly absorbed, would suffice to melt one millionth part of a metre in thickness, from the surface of a sheet of ice horizontally exposed to its action per minute of mean solar time...
Página 581 - Yet there is one point to which we should wish that some attention might be paid, — it is the sudden gush of rain which is almost sure to succeed a violent detonation immediately over-head. Is this rain a cause or...
Página 578 - ... explosions ; and the two balls between which the discharges pass can be easily regulated, as to their distance from each other, by a screw. After a certain number of explosions, say of negative electricity, which at first may be nine or ten...
Página 580 - ... the negative above, as the case may be : and this discharge may take place, according to the laws of Electricity, through any or all of the surrounding zones, without influencing their respective electricities otherwise than by weakening their force, by the removal of a portion of the electric fluid from the central nucleus above to that below : every successive flash from the cloud to the earth, or from the earth to the cloud, weakening the charge of the plate of air, of which the cloud and...
Página 549 - ... a graphical projection the law of diurnal increase and diminution of the solar radiation, which will thus readily become apparent, provided the perfect clearness of the sky continue, — an indispensable condition in these observations, the slightest cloud or haze over the sun being at once marked by a diminution of resulting radiation. To detect such haze or cirrus, a brown glass applied before the eye is useful, and by the help of such a glass it may here be noticed that solar halos are very...
Página 584 - ... from one extremity to the other the brightness of the rays would increase successively in intensity. This luminous current would appear several times in quick succession, and it would pass much more frequently from west to east than in the opposite direction. Sometimes, but rarely, a retrograde motion would take place immediately afterward ; and as soon as this wave of light had run...
Página 578 - On the approach of a thunder cloud to the insulated atmospheric wire, the conductor attached to it, which is screwed into a table in my electrical room, gives corresponding signs of electrical action. In fair cloudy weather the atmospheric electricity is invariably positive, increasing in intensity at sun-rise and sun-set, and diminishing at midday and midnight, varying as the evaporation of the moisture in the air : but when the...
Página 2 - ... obscure points, he might hope to arrive at a general view. The questions that we would address to nature, are the very experiments of which we are deprived in the science of meteorology.

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