APPENDIX TO METEOROLOGICAL AND HYDROGRAPHIC TABLES. 



21c 



Table 18 A. Change of isobaric charts, given in millimeters of mercury for sea level, into charts of 

 dynamic topography of the 7000 m-bars isobaric surface. 



Given the isobaric chart in millimeters of mercury and the isothermic chart, centigrade, both for sea-level, the 

 latter reduced to sea-level under the supposition of a fall of temperature of 0.5 C. for every hundred dynamic meters of 

 height. On account of the smallness of the reductions no distinction between true and virtual temperature is required. 



( 1) Required the level curve of height o on the 1000 m-bars surface. The table shows this curve to be identical 

 with the isobaric curve of 750 mm. pressure. 



(2) Required the level curve of height 250 dynamic meters on the 1000 m-bars surface. The table shows that it 

 passes closely by the points of intersection of the isothermic curve 50 and the isobaric 780 mm.; the isothermic 

 40 and the isobaric 779 mm.; the isothermic 30 and the isobaric 777 mm., and so on. 



(3) Required the level curve of height 150 dynamic meters on the 1000 m-bars surface. The table shows that 

 it passes closely by the points of intersection of the isothermic curve 50 with the isobaric 733 mm. ; of the isother- 

 mic curves 40 and 30 with the isobaric 734 mm.; of the isothermic curves 20 and io with the isobaric 735 

 mm., and so on. 



The main result is a close accordance of the level lines for the interval of 50 dynamic meters with the isobaric 

 lines for the interval of 5 mm. of mercury. 



