Smithsonian miscellaneous collections . 02 ->t~a¥ ft \ \ —H—? 1 V / / / f I 1 UP •?. FIG. 40 MOVEMENTS OF ATMOSPHERE GULDBERG AND MOHN 225 By the aid of this table we have constructed for every thecurves of equal variation shown in fig. 41. FIG. 41 We can also determine the curves of equal variation by construc-ting two systems of isobars for given dates. §33. Isotherms of systems of wind Permanent systems of wind demand a uniform temperature for theair that enters into the barometric minimum. Assuming that thetemperature of the air varies with the pressure when nearest thes
Smithsonian miscellaneous collections . 02 ->t~a¥ ft \ \ —H—? 1 V / / / f I 1 UP •?. FIG. 40 MOVEMENTS OF ATMOSPHERE GULDBERG AND MOHN 225 By the aid of this table we have constructed for every thecurves of equal variation shown in fig. 41. FIG. 41 We can also determine the curves of equal variation by construc-ting two systems of isobars for given dates. §33. Isotherms of systems of wind Permanent systems of wind demand a uniform temperature for theair that enters into the barometric minimum. Assuming that thetemperature of the air varies with the pressure when nearest thesurface of the earth, it is evident that a permanent cyclone musthave circular isotherms around its center. Moreover, the systemof isotherms must itself be permanent. If we consider a variable and stationary cyclone, the isothermsmust be circular around the barometric minimum but they can vary 226 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 with the time, so that the curves of equal variation of temperaturemay be concentric circles around the center of the cyclone. In the general case where the isotherms have at first any situa-tion whatever, the system of wind is mobile, and the trajectoryof the barometric minimum depends on the situation of the is
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Keywords: ., bookauthorsm, bookcentury1800, bookdecade1860, booksubjectscience
