EXAMPLES OF SOLENOIDAL FIELDS. 



39 



supposed to represent the projections of vertical walls separating from each other 

 a set of tubes of flow. A third set of lines is then drawn, representing the height of 

 these tubes. The curves for the equal height of the tubes will be a new set of con- 



* i * 



j i i i r r i 



Fig. 43. Field with singular point in space represented by different charts in horizontal projection. 



A. Surface of flow represented by contour-lines (circles) and containing lines of flow (radii) and curves of equal 



intensity (stippled circles). 



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



and lines of flow (radii). 



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



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



(circles). Normal component constant and not represented. 



