216 Transactions of the Boyal Society of South Africa. 
Over a quarter of a century has now passed since the inception of the 
undertaking, and the work is not yet half done. When it is finished it 
will prove of inestimable value to astronomers, not only as giving them an 
exact picture of the sky as v/e see it now, but also affording material for 
an exhaustive consideration of those great cosmic problems that are 
arising, clamant, for settlement : it will also remain an abiding monument 
to the genius of the man who first realized its possibility and inspired 
its progress. 
But as we have said, the larger scheme nearly wrecked the lesser. 
The Eoyal Society, in view of the fact that a photographic survey of 
the whole sky was in contemplation, refused to continue their grant for a 
survey of a portion only. They considered that there was no need for a 
more restricted Durchmusterung. A few prominent astronomers also 
thought that the lesser survey, if successful, might prejudice the greater. 
In vain Gill pointed out that they would all be dead before the great star 
map was finished ; that his southern survey was for immediate use ; that 
there was a great need for a catalogue of stars down to the tenth 
magnitude. 
The grant was withdrawn, and for many years Gill had to support 
the enterprise from his own private resources. The result was that in 
extent and in quality it was to some extent curtailed. 
The complete Durchmusterung was published in three large volumes, 
and in 1902 the Eoyal Astronomical Society marked its high appreciation 
of the value of Kapteyn's splendid work by awarding to him its gold 
medal. 
Of his self-sacrificing labours Gill says : — 
" Probably the most valuable result of the Cape Photometric Durch- 
musterung to science is the fact that its preparation first directed 
Kapteyn's mind to the study of the problems of cosmical astronomy, 
and thus led him to the brilhant researches and discoveries with which 
his name is now and ever will be associated.^' 
We would make but one slight alteration to this worthy tribute : we 
would couple Gill's name with Kapteyn's. 
We have considered the salient matters that made up Gill's life at the 
Cape out of their chronological order, as his disposition was to keep two 
or three enterprises going at one and the same time. This change of 
mental position seemed to afford him a kind of relief. 
The enterprises of secondary importance, if one may be allowed to 
make such a distinction, that occupied his attention were so numerous 
that one, in a brief memoir, must only select those that were typical of his 
mental attitude and his observational skill. 
An investigation that interested him early was a determination of the 
mass of Jupiter, and of the orbital elements of its older satellites. As far 
