( 849 ) 



I may remark in passing that Van der Lee's observations for water 



and phenol illustrate the case discussed here, and that through the 



existence of a maximum pressure the properties of the vapour-liquid 



binodal line give evidence either of the occurrence of the asymptote 



dp 

 of the line — =■ in the v^-diagram, or of its lying not far to the 

 dx 



left. So there are 4 plaitpoints after the appearance of this double 



plaitpoint. So two serve as plaitpoints of the plait which is detaching 



itself and they are both realisable according to our nomenclature 



and when detachment has taken place, both can actually be realised. 



They serve then as plaitpoints of what must properly be called a 



longitudinal plait. The two other plaitpoints, viz. the hidden plaitpoint 



which we placed in the neighbourhood of the points 2 and 3 above, 



and the lowest of the newly formed plaitpoints then form a couple 



of heterogeneous plaitpoints, which do not show themselves on the 



binodal curve of the vapour-liquid plait and will soon coincide and 



then disappear. From this moment the binodal lines of the two plaits 



are quite separated and behave independently of each other. The 



vapour-liquid plait is then simple and perfectly normal. But also the 



longitudinal plait may then be considered as a normal one. 



{To be continued.) 



Waterstaat. — "Velocities of the current in an open Panama canal." 

 By Dr. C. Lely. 



(Communicated in the meeting of March 30, 1907). 



§1. After an elaborate investigation the American Government has 

 resolved on the execution of a project of a Panamacanal at liiüii 

 level, viz. at a height of 85 feet (25.9 M.) above the mean sea level. 

 It will have three flights of locks. 



Against this project of the minority of the Board of Consulting 

 Engineers of 1905 there was a counterproject of the majority which 

 favoured a canal at sea-level or rather a canal with one pair of locks. 

 This canal would have been provided with one pair of locks in order 

 to separate the Atlantic Ocean from the Pacific, but for the rest it 

 would have been in open communication with these seas on both 

 sides of the locks. 



As a matter of fact this canal would not have been an open canal, 

 therefore, like the Sue/ Canal, but a canal in which in most cases, 



58* 



