( 872 ) ' 



If, in consideration of this fact, we substitute in the second memoen 

 of the formula, for v the values observed in llie period L87 J — 1876 

 increased by 20 percent, we finally find 



7 a hour before low water (r, — r) = 0.33 M. 

 at „ .. (v, — v) = 0.13 M. 



The differences 0.33 and 0.13 M. represent the differences of the 

 simultaneous velocities, not those of the maximum velocities at the 

 distances of 64 and 28 K.M. from the Atlantic. 



At the moment that the velocity reaches its maximum at K.M. 64, 

 the velocity at K.M. 28, where the tides set in about an hour later, 

 will still be below the maximum at that place. According to the 

 observations on the Suez-canal we may assume that, at the epochs 

 mentioned, the velocities of the current at K.M. 28 will at least he 

 about 0.15 M. and 0.05 M. below the maximum ofthatplace. Hence 

 we may conclude that the maximum velocities at K.M. 64 and 28 

 will certainly not differ 0.18 .M, and probably not much over 0.08 M. 

 We are sufficiently justified therefore in assuming that the velocity 

 ,U K.M. 64 may be about O.J5 M. in excess of that of K.M. 28. 



As appears from what has been stated before the difference is 

 inferior to the increase of the velocity of the current on the Suez- 

 canal under the influence of the wind, which may amount to 

 0.30 — 0.50 M. It cannot, therefore, cause any serious difficulty. 



§ 7. For an open Panama-canal executed as follows: 



From the Atlantic to K.M. 64 having the same normal cross section 

 as that of the project for the sea-level canal; 



from K. M. 64 to K. M. 68, which is the place where the canal 

 will be connected with a lake gradually widening; 



from K.M. 68 to the Pacific at K.M. 80 having bottomwidth 

 of 400 to 500 feet; 



the following conclusions in regard to the velocities of the current 

 at springtide may be accepted : 



On the first 28 K. M. of such an open canal, velocities of the 

 current will occur at springtide which, on an average, will be about 

 equal to those, which will take place at spring tide and with a moderate 

 wind on the Suez-canal between the Bitter Lakes and the Red Sea 

 as soon as the widening of this canal will be complete. 



On the subsequent 36 K.M. of such an open canal the maximum 

 velocities at springtide will exceed those on the preceding part by 



