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Astronomy. — “On « peculiar anomaly occurring in the transit 
observations with the Leiden meridiancircle during the years 
1864—1868. By E. F. van DE SANDE BAKHUYZEN and J. E. 
DE Vos VAN STEENWIJK. 
(Communicated in the meeting of June 24. 1916.) 
1. Introduction. 
Not many years after the mounting of the meridiancirele at the 
Leiden-observatory and the completion of a number of auxiliary 
apparatus according to designs by Kaiser a beginning was made 
with the observation for an extensive Fundamental Catalogue. For 
this purpose a list of 166 stars was drawn up (mainly the list of 
the Nautical Almanac as far as visible at Leiden) containing 24 
circumpolar stars which were to be observed in both culminations. 
The observations began in February 1864 and were considered 
as completed in July 1868. The number of observations had been 
15870 of which about 12800 pertained to the fundamental stars 
and 579 to the sun. 
All these observations were published — although for the greater 
part unreduced — in 1868 in the Annals of the observatory, 
Vol. I. Soon afterwards, however, a beginning was made with the 
reduction of a limited number of the declination-observations, and this 
reduction, with a full discussion of the results, which gave rise to 
important investigations by Kaiser and his collaborators, appeared 
in 1870 in Volume 2. A complete reduction was even then designed, 
but — apart from an addition to the results of Vol. 2 according to 
calculations by Dr. VALENTINER — it was not till 1876 that the 
project, including a complete reduction of all the declination-observa- 
tions of the fundamental stars and of the sun, was actually taken 
in hand. In 1879 the work was for the main part completed and 
a short account of it was given by the first of us in his thesis for 
the doctorate published in the same year containing a determination 
of the Obliquity of the Eeliptie according to the Leiden declinations 
of the sun. The complete reduction of the declination-observations 
of the stars was then published in 1890 in Vol. 6 of the Annalen; 
the discussion of the final results, although for the greater part 
completed even then, has not yet been published. 
Whereas the reduction of the declination-observations of the years 
1864—1868 had thus been completed within a comparatively short 
period, the observations of the right-ascensions on the other hand 
remained for the greater part unreduced. Apart from the reduction 
