RicHarpson—Lines of Flow of Water in Saturated Soils. 315 
the surface is steady, as in the cases discussed in the foregoing 
section on drainage, it is not easy to foresee what shape they will be, 
except in certain instances—for example: the surface of a wall of 
peat from which water is oozing out is covered by a layer of water 
outside the peat, and of negligible curvature, so that the surface- 
tension there is of no effect. But what of the upper surface 
in the cylindrical block used in determining the conductivity ? 
The theoretical water-line shown in the diagram had no real 
existence; the whole block was saturated. Some principle is 
required to determine the pressure due to capillarity as a function 
of position on the surface, and thus to find the corrected flow out 
of the cavity. 
§ 8. ConcLuUsion. 
In conclusion, I should like to thank Dr. Gilbert J. Fowler, 
who has kindly given me the reference to Pennick’s paper quoted 
in the bibliography. 
§ 9. BrpLiogRAPHy. 
Boussinksq, J.: 
1902. “Sur le débit, en temps de sécheresse, d’une source 
alimentée par une nappe d’eaux d’infiltration.”” Comptes Rendus, 
Acad. Sci., Paris, exxxvi., p. 1511. 
1903a. ‘‘Sur un mode simple d’écoulement des nappes 
d’eau. . . .” Comptes Rendus, Acad. Sci., Paris, exxxvii., p. 5. 
1903b. “Sur la stabilité d’un certain mode d’écoulement 
d’une nappe d’eaux infiltration.” Loe. cit., exxxvii., p. 101. 
1904a. “Equations générales...” Loc. cit., exxxix., p. 387. 
1904b. ‘* Hquation de deuxiéme approximation ...” Loe. 
eit., Cxxxix., p. 417. 
1904c. “ Petites dénivellations d’une masse aqueuse infiltrée 
dans le sol, de profondeurs quelconques .. .” Loc. cit., exxxix., 
p. 441. 
1904d. “Application . . . aux fortes sources des terrains 
perméables ...” Lic. cit., exxxviii., p. 117. 
