OCR Text |
Show 156 As a general rule, we see, with the decrease of the absolute amount of moisture, an increase of the daily difference of extremes, as shown in the following table: Locality. Date. Absolute humidity. 7.8 12.9 6.0 15.1 11.7 13.6 Difference of extremes. Fahrenheit 44^. 00 15.00 39.00 18.00 97.00 90.00 Cottonwood Islands , Stone's Ferry Bhadames in the desert Sahara, ( Bfcolfs) July 19 July 97 Aug. 6 Aug. 19 Aug. 15 Aug. 18 In some cases the differences of daily extremes stood nearly in inverted proportions to the square of absolute humidities; in other instances, especially when two cases with widely differing absolute humidities were compared, the differences of the daily extremes stood nearly in inverted proportion to the simple absolute humidities. A lav expressible by a mathematical formula can only be found, however, after a long series of very careful observations. It is natural that only observations made at one and the same locality and in the same season can be compared with each other. In regard to the ozone, none, or but very weak reactions, were obtained when the temperature rose above 106° F., which failure is either due to the volatilization of the iodine from the test- papers prepared with iodide- of- potassium starch, or to the real absence of ozone; however, during cool nights moderately strong reactions were obtained in midst of the desert. |