Sole use of the 87½-centime surcharge on the one-franc Marie Adélaïde definitive

Why do we see so many covers—all philatelic creations—franked with the 30c Marie Adélaïde definitive surcharged to 17½c in combination with the one-franc surcharged to 87½c? There was no one-franc-five-centime rate, yet dealers often put optimistically high prices on these plentiful philatelic souvenirs.


The explanation is straight forward, and nicely explained in Hans von Rudolphi’s scholarly tome — Handbuch der Briefmarken-kunde: Lieferung 16/17 - Luxemburg, published in 1944. Here is a summary.

In July 1916, two new rates to Germany took effect: a 17½c letter rate and an 87½c rate for parcels weighing up to 5 kg. But to pay the latter rate, the 87½c William IV definitive (issued 6 Jun 1908) was no longer available. This stamp had been surcharged to 62½c on 29 Feb 1912. So to meet the immediate need for an 87½c stamp, Luxembourg on 14 Aug 1916 released the one-franc Marie Adélaïde definitive surcharged to 87½c (the 30c stamp was surcharged to 17½c to pay the new letter rate).

The 17½c and 87½c Marie Adélaïde definitives did not appear until 1 Mar 1917. Thus, the most interesting sole uses of the 17½c and 87½c surcharges are on letters and parcels sent to Germany between 14 Aug 1916 and 1 Mar 1917. And the most challenging use of the two by far is a proper sole use of the 87½c surcharge since very few parcel cards were saved.

The parcel card seen here is illustrative. It’s a proper sole use of the 87½c surcharge with the stamp paying the postage from Luxembourg-Limpertsberg, 2 Nov 1916, for a 950 gram parcel sent to Herne in Westfalia, Germany. The back shows the Luxembourg-Gare 3 Nov 1916 transit, the Trier, Germany, transit of the same date, and the Herne cds of 6 Nov 1916 documenting the arrival of the parcel.

Sole use of the 17½c/30c surcharge

Echternach II, 21 Sep 1916 to Trier, Germany

Typical Souvenir Cover Using the
17½c and 87½c Surcharges in Combination

Luxembourg-Ville IV to Berlin, 2 Oct 1916

An unreported 'Mondorf-les-bains' single line mark!

Today I was studying a group of covers franked with the 1916-1924 surcharges.  And it's when you study material you've acquired, perhaps long ago, that you often make new discoveries.

Here is a cover that initially interested me because the 17½c 20g letter rate and 25c registry fee to Germany were paid entirely with 1916-1924 surcharges.  But then I noticed something I hadn't seen before -- a curious single line strike reading 'Mondorf-les-bains' next to the registry mark.  There was also the Mondorf-les-Bains cds of  December 1, 1919 (and a Luxembourg-Ville transit backstamp of the same date).  So what purpose did the single line mark (with "Bains" strangely spelled with a lower-case "b") serve?

The strike remains a mystery for me.  Two numbers are written on the cover.  'No. 4' appears in black ink above the single line mark.  And above the registry mark in purple pencil '574' is written, which I assume  is the registration number.

Also, the cover is addressed to a philatelic organization (I think) in Ludwigslust (Mecklenburg), Germany.  Did the sender apply the single line mark before registering the cover?  And if so, why?

I occasionally see stamps canceled with a single-line device, presumably because the proper canceler was unavailable, but here the device was not used to cancel the stamps.

Got any clues?