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We have usually a warm and agreeable sensation of the atmosphere with such Rain, which is strikingly contrasted to the cold and raw sensation occasioned by the fall of thick wet mists, or Rain which happens when, even with a Northern or Easterly Wind, the Barometer and Thermometer sink together, and when the air has previously been found to be either negatively, or nonelectrified.
As far as we can determine, the air appears capable of holding more water in solution, in proportion as its temperature and pressure is greater; and yet the Thermometer often rises when Rain is coming on, particularly in winter. This circumstance is not wholly irreconcilable with what has been laid down, since the Rain may be occasioned by a diminution of pressure, as is often manifestly the case, the Barometer falling, or else by a supervening current of colder or supersaturated air; and the rise of the Thermometer, which accompanies the fall of the Barometer in this case, may be owing to the increase of temperature produced by the con
produces this smell the strongest; and it is weakest with the cold, and, perhaps, nonelectric Rain, which sometimes falls after the condensation of a spreading sheet of cirrostratus into nimbus, with a cold atmosphere.
densation of the vapour in the case of Rain. But on what principle can we account for the increase both of Temperature and Pressure, during such condensation? On the 20th and 21st July, 1811, Rain kept falling in large drops almost all day, with a rising Barometer, and no depression of Temperature, (making allowances for the interception of the Sun's rays,) while evaporation continued to be considerable.
It has been remarked by M. Howard, that if the state of the Barometer, during any period of the Moon, be examined, it will be found to have been highest or lowest about the time of the Full and New Moon, as may happen; but that the mean state of that instrument usually happens about the lunar quadratures. As far as my own observations enable me to decide this connexion is observable in the majority of instances.
I once thought that the mean state of the Barometer of a given number of day's observation varied, in some measure, according to the Moon's perigee and apogee; that is, that it was higher with the latter than with the former : but subsequent researches convinced me, that the exceptions were almost as numerous as the cases corresponding to the rule.
There is yet another observation on the Barometer worthy of record. It is said, that if a number of daily observations be taken, the average maximum for any period will be found to take place at noon, and the minimum at nine o'clock in the morning, and the next lowest at six in the evening.
I introduce the above circumstances here, merely that they may become the subjects of the future observations of meteorologists in different places; as I think they are worthy of stricter examination than has hitherto been made.*
* If the place of the Moon has such an effect on the atmosphere, as to influence the barometrical pressure, it may probably produce other varieties in the state of the air, which may influence the nervous system and animal functions of persons in particular kinds of disease. It is thus that it may have an effect on persons of such deranged intellect, as is termed lunacy, who are said, in some cases, to be worst about the full of the Moon.
There are many other instances of periodical paroxysms of different complaints, and some of them very curious; but how far, and in what manner, solar and lunar influence is concerned, cannot be precisely determined. Some persons have had paroxysms come on at particular hours of the night, and have, for a long time, awoke at those hours. To try how far the imagination has been concerned in producing the diseases, clocks have been altered to deceive the patient, but
without avail. The reader may consult the Zoonomia of Darwin, and a recent work in France, by Ph. Pinel, Arnold on Insanity, Crighton on Mental Derangement, and others who have written on this subject.
Since the first edition of this book, I have conversed with Dr. Spurzheim, about the periodicity of disorders of health. He considers it as more or less affecting every body. The reader may refer to a large work on the newly discovered Anatomy and Physiology of the Brain, published by him, entitled, Physiognomical System, &c. 8vo. Baldwin & Co. London, 1815.-Also Observations on the Casual and Periodical Diseases ascribable to Atmospheric Influence, 8vo. London, 1817.
OF SEVERAL SUPERSTITIOUS NOTIONS WHICH APPEAR TO HAVE HAD THEIR ORIGIN IN AN OBSERVANCE OF CERTAIN METEOROLOGICAL PHAENOMENA.
A NATURAL tendency exists in the human mind, arising from the mutual influence of the different organs of the Brain, and the consequent association of ideas, to attach notions of good or evil to those objects which have been observed to precede or to accompany pleasurable or painful circumstances: hence the origin of many superstitious opinions.*
From such association of ideas many animals were anciently worshipped, either as gods or evil spirits; and even at a later period, when their worship was rejected as superstitious, or useless, they were considered as foreboders of
* In the figurative language of the ancients, facts were often ascribed to contemporaneous remarkable circumstances; hence the influence of Procyon or Dog Days, the blustering of the stormy Orion, and many others; see a Memoir Sur l'Origine des Constellations et l'Explication de la Fable, by M. Dupuis.