4 2 



DYNAMIC METEOROLOGY AND HYDROGRAPHY. 



the lines of flow contained in these hyperbolic surfaces and projecting themselves 

 on the horizontal plane as exponential curves is thus easily conceived. Adding the 

 lines of equal intensity (stippled straight lines), we get a complete representation 

 of the field contained in these hyperbolic surfaces. 



x i ? *-t * 5 ** r-* * J > 



1 J Z > 3 



C D 



Fig. 45. Field with asymptotic line in space, represented by different charts in horizontal projection. 



A. Surface of flow represented by contour-lines (straight) and containing lines of flow (exponential curves) and 



curvesof equal intensity (stippled straight lines). 



B. Tubes of flow represented by contour-lines for absolute and for relative topography (full-drawn and stippled 



straight lines), and lines of flow (exponential curves). 



C. Horizontal section through the system of tubes of flow. 



D. Two-dimensional field in horizontal plane represented by lines of flow (exponential curves) and curves of equal 



intensity (straight lines). 



