IX 
portance in his papers, gives eloquent evidence not only of the 
untiring energy he would- display in order to have every single 
case perfectly clear, but also of the enormous correspondance which 
ringing involves. In this as in many other kinds of work he had 
an excellent helper in his wife, late Miss Ingeborg Lemming, 
whom he married in 1891, and who entered into her husband’s 
interests with rare enthusiasm. 
In a surprisingly short time Mortensen’s ringing system was 
adopted abroad; already in 1903 Thienemann began ringing in 
Rossitten at Kurisches Haff, in 1904 J. H. G u r n e y in England, 
in 1908 Kgl. Ungarische Ornithologische Centrale, and then fol- 
lowed without intermission a great number of different societies in 
all parts of Europe, and even in North America. The number of 
birds thus ringed has recently been estimated by competent author- 
ity at more than 100,000; it seems, however, not unlikely that 
this number, especially regarding certain later English statements, 
may be redoubled. 
As an instance of Mortensen’s reputation abroad we may end 
by mentioning that a short time ago our country was encouraged 
by Austrians of note to start an international collection, in order 
to provide the necessary funds for a memorial tablet to be placed 
possibly on the house where he lived. Unfortunately, present con- 
ditions do not seem propitious for the realisation of this fine pro¬ 
position. 
