The present joint paper contains the results of a discussion of some of the more salient meteorological aspects of a variation in the range of air temperature. The investigation was instituted with the primary object of determining what variation, if any, of the diurnal curve of barometric pressure might accompany a greater or less range of temperature as night followed day; but other points had necessarily to be considered so that we might be able to assign as nearly as possible the position

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... the range curve in the sequence of meteorological cause and effect. We have, however, adhered to our original intention of making the range of temperature the basis of the argument. The meteorological elements taken into account here are the monthly means of:-1. The diurnal range of air temperature; 2. The maximum temperature of the air; 3. The minimum temperature of the air; 4. The hourly mean temperature of the day; 5. The range of dew-point temperature from VIII. to XIV. ; 6. The hourly mean dew-point temperature; 7. The range of relative humidity from VIII. to XIV. ; 8. The hourly mean relative humidity; 9. The range of barometric pressure from VIII. to XIV. ; 10. The hourly mean pressure; 11. The mean percentage of sunshine; 12. The mean percentage of cloud derived mainly from six observations a day; 13. The mean rainfall ; 14. The total rainfall in the period studied. Downloaded by [University of Arizona] at 17:40 19 April 2015 2. The maximum temperature; 4. The mean temperature; 9. The range of pressure; 11. The duration of sunshine. The following decrease more or less regularly as the range of temperature increases:-3. The minimum temperature; 5. The range of the dew-point; 6. The mean dew-point; 7. The range of relative humidity; 8. The mean humidity; 12. The cloudiness of the sky; 13. The mean rainfall ; 14. The number of rainy days in a month. The one exception is the mean pressure of the month, which commences by falling, but concludes by rising as the range of temperature increases in magnitude. Whether this anomalous behaviour of the Downloaded by [University of Arizona] at 17:40 19 April 2015