Comments on the Ludecke et al paper
http://www.clim-past.net/9/447/2013/cp-9-447-2013.pdf
In the graph below
-Red up/down arrows
show start and end of ~150 year long period, during which if the Central European temps are lifted by ~0.5 C,
then there is an almost perfect match to the CET for the same period.
Considering that London Paris distance is only 200 miles, it is unlikely that such sudden change could happen
in short few years and endure 150 years at precisely same 0.5C difference, otherwise the temperatures change agree in every minute detail. I suspect that data conversion from the old European temperature scales may be the critical factor here.
The Reaumur scale was in a widespread use in Europe, particularly in France and Germany.
