THE SEINE, THE HEUSE, AND THE MOSELLE 
235 
branches that once belonged to the INIense. The diverters (by 
which the Toul was given over to the Moselle and the Aire to 
the Aisne) may be called the Pompey and the Grand Pre re- 
spectively, the latter ultimately delivering its prize through the 
Marne to the Seine. The beheaded streams of the two are the 
Pagny and the Bar. The former is so insignificant that I have 
had to invent a name for it, finding no name for the stream but 
only the “ IVlarais de Pagny ” entered on the Etat-major map of 
1 80,000. The Bar is the best example that I have ever seen 
of a beheaded stream trying ineffectually to live up to the robust 
habits of its great predecessor. 
The diminished Meuse again . — The loss suffered by the Meuse 
and the increase gained by the Seine through the diversion of 
the Aire are of no great moment, but as far as they go they serve 
to confirm each river in the habits that now characterize it — the 
IMeuse in staggering with uncertain steps around its valley curves, 
the Seine and the Moselle in swinging boldly around their curves 
and undermining the inclosing bluffs. It should be noted, how- 
ever, that when a large tributar}^ is diverted from a point high 
u[) on the trunk of a main river, the loss of volume that the 
change produces may be a large fraction of the total volume that 
once belonged to the main river, and hence that the loss may 
greatl}' affect the ability of the main river still to follow the 
swinging valley tliat it cut out when its volume was greater. 
On the other hand, when a tributary of relatively small volume 
is diverted from some point near the middle of the main river, 
the loss thus occasioned will be a comparatively small fraction 
of tlie trunk volume, and tlie change of habit thus produced 
will be corresi)ondingly small. It is for this reason that the 
staggering of the Meuse near Commercy is so much more marked 
than between Sedan and Mezieres. The loss of the Toul (upper 
Moselle) was a much more serious affair for the Meuse than the 
loss of the Aire. 
Sapideinentarij problems . — There are certain aspects of this ])rol)- 
lem tliat remain to be considered briefly. First, are there any 
other examples of branches diverted from the system of the 
Meuse to those of its neighliors on the west and east? Although 
I have been unable to find any direct signs of them on the maj), 
there still does seem to be indication that other diversions have 
occurred. On looking at the Meuse above Pagny, it is there 
almost as much out of proportion to its valley as it is below 
Pagu}’. It is po.ssilde, therefore, that other headwater branches 
