Mr. Symons pointed out that although it might be useful to trace the origin of some of the weather proverbs, it would be extremely difficult and perhaps impossible, as some of them were ancient. With regard to the connection between lunar halos and rainfall, he thought that it would be curious, considering the large number of wet days in this country, rain falling on an average every other day, if some of them did not happen to follow lunar halos. Respecting doors and windows sticking in damp weather, this was rather the result of existing damp than a forecast of more damp to come; for if existing damp foretold coming damp it was not easy to see how dry weather could ever occur. With regard to visibility, he was glad the authors had referred to Mr. Cruickshank’s observations at Aberdeen, extending over twenty-one years, and Mr. Symons thought that much might be learned from a thorough discussion of similar observations.
Mr. Wilson directed attention to Professor Tyndall’s theory, that audibility was due to the homogeneity of the atmosphere.
Mr. C. Harding thought that the paper would be useful to an isolated observer, whose forecast was dependent upon his own observation. It appeared to him that in classifying the prognostics, the authors of the paper had rather begged the question—given a certain occurrence which was admittedly a prognostic of bad weather; this seems to have been consequently classed as belonging to the front half of a cyclonic disturbance. He suggested that with each occurrence of the prognostic in question it would be better to note the existing conditions of atmospheric distribution, and, finally, to classify by actual observation. He stated that the form of isobars described by the authors as wedge-shaped had been referred to many years ago in various publications, by Captain Toynbee, as a “ridge” of pressure. Some distinction should have been made between the weather of anticyclone in summer and in winter, as it differed materially. Audibility had been referred to as a sign of bad weather; he might say that it was notorious in ballooning that for a given distance sounds could be heard more distinctly than on the earth, and in a recent ascent he had noticed that the shrill voices of children were much more audible than the voices of grown persons.
Mr. Abercromby, replying, said that Doctor Tripe’s analysis of halos was interesting, but that if rain did not fall within twenty-four hours after a halo, any rain after that would not be due to the cyclone which produced the halo, but to a new one. Damp walls were certainly due to excess of vapor, not to rapid changes of temperature. Soot was doubtless blown down by wind, but when used as a prognostic it rather referred to soot falling out of doors, and was to be attributed to excessive damp. Halos were unquestionably due to the presence of a thin film of ice-formed cloud, and not merely to the amount of moisture in the air. This ice film was only formed in front of cyclones or thunder-storms, and for that reason was a sign of rain. With regard to visibility alluded to by several speakers, he could not admit that it was due to excessive moisture, for the hygrometer showed that it was not so. He agreed with Captain Toynbee, so far as believing that there was a descending current of dry, clear air with a northwest wind on the front side of a “wedge,” but he doubted if that was the whole explanation. In the centre of anticyclones there was also a descending current of dry air, but no “visibility.” The diagram of straight isobars was given for westerly winds, as that type was by far the commonest. Like every other shape of isobars, the details varied with the type of weather in which they occurred. In an elementary paper it was considered inexpedient to go into so much detail. In the case mentioned by Mr. Scott, isobars trending east and west, but sloping towards the south, the same broad features as given in the diagram would be reproduced, but with a harder sky and an east or northeast wind. The prognostics would, however, be much more likely to fail, for cyclones in the northerly or easterly types, to which such isobars would belong, did not follow with the same regularity as in the westerly type. The refraction, which was a prognostic of east winds on the southwest of an anticyclone, was very different from the refraction on the northwest edge of a cyclone, which portended a fresh storm. The chief difference was the haziness of the horizon in the former case as compared with its visibility in the latter. The latter kind was hardly known on the south coast of England. He strongly suspected that the condition common to both kinds was a relatively cool air over a comparatively warm sea. The type of isobar which exhibited incipient “bights” or imperfect secondaries, was doubtless that most frequently associated with thunder-storms, but the kind of thunder-storms alluded to in the paper as showing no trace on the isobars undoubtedly occurred. Any reference to cloud or sky colors was intentionally omitted in this paper, as also to prognostics relating to diurnal winds. Candles burned badly before rain, probably owing to a stagnant, damp air. Blue flame was owing to the formation of carbonic oxide when a fire burned very red on a frosty night. Doors and windows sticking in damp weather indicated rain because damp preceded the rain area of a cyclone.
The idea suggested by Mr. C. Harding, that because certain prognostics were known to be associated with bad weather, therefore they were classed as belonging to the front of a cyclone, was entirely erroneous, and exactly opposite to what had been done. The method Mr. Abercromby had adopted for the last twelve years had been, when he observed a good example of any prognostic, to make a note and put it by with the nearest synoptic chart for the day, or often with both the preceding and succeeding charts. When a sufficient number had been collected, the charts were examined, and the necessary deductions drawn from them. Thus the charts were classified according to the prognostics associated with them. The results of all these researches had been embodied in the paper, and the important fact deduced was that every portion of every shape of isobars had a characteristic weather and appearance. The general fact of a “wedge” being associated with fine weather had been noticed many years ago by Captain Toynbee, but the details of weather in different portions, and their relations to prognostics, had a considerable amount of novelty.
Mr. Marriott said that it would be impossible to give the authorities or sources from which all the sayings in the paper had been derived, but the foot-note on page [23] contained a list of the works from which the quotations had been made. The authors on the present occasion had only dealt with certain classified prognostics; and this would explain why many others had not been noticed. They hoped, however, to deal with these in a future paper.
POPULAR WEATHER PROVERBS AND PROGNOSTICS.
PROVERBS RELATING TO ANIMALS.
Ass.
An old adage says: