Sorry, but I give myself the answer to my previous query n.2.
At p.254 of his 1936 Econometrica paper "The general welfare in relation to 
taxation", Harold Hotelling used the expression "dead loss" to identify 
what, as he said, was "the sum of the areas of the shaded triangles in the 
older graphic demonstration". A few lines later he calls this area "a dead 
loss".

I assume there is no real difference in English between "deadweight loss" 
and "dead loss".

Note that the latter had been used several times before Hotelling's paper. 
In particular, by F.Y. Edgeworth who, in his 1910 Economic Journal's paper 
"Application of probabilities to economics - II", in the context of the 
analysis of price discrimination by a monopolist, translated at p. 453 as 
"dead loss" the expression "perte seche" that he attributed to Colson (not 
to Dupuit).

Nicola Giocoli