PRESIDENT’S ADDRESS. 23 
As the result of the Congress of Astronomers held at Paris in 1887 
some sixteen of the principal observatories in the world are engaged, as 
is well known, in the laborious task, not only of photographing the 
heavens, but of measuring these photographs and publishing the relative 
positions of the stars on the plates down to the eleventh magnitude. 
A century hence this great work will have to be repeated, and then, if 
we of the present day have done our duty thoroughly, our successors will 
have the data for an infinitely more complete and thorough discussion of 
the motions of the sidereal system than any that can be attempted to-day. 
But there is still needed the accurate meridian observation of some eight 
or ten stars on each photographic plate, so as to permit the conversion of 
the relative star-places on the plate into absolute star-places in the heavens. 
It is true that some of the astronomers have already made these observa- 
tions for the reference stars of the zones which they have undertaken. But 
this seems to be hardly enough. In order to co-ordinate these zones, as 
well as to give an accuracy to the absolute positions of the reference stars 
corresponding with that of the relative positions, it is desirable that this 
should be done for all the reference stars in the sky by several observa- 
tories. The observations of well-distributed stars by Kustner at Bonn 
present an admirable instance of the manner in which the work should 
be done. Several observatories in each hemisphere should devote them- 
selves to this work, employing the same or other equally efficient means 
for the elimination of sources of systematic error depending on magnitude, 
&e., and it is of far more importance that we should have, say, two or 
three observations of each star at three different observatories than two 
or three times as many observations of each star made at a single 
observatory. 
The southern cannot boast of a richness of instrumental and personal 
equipment comparable with that of the northern hemisphere, and con- 
sequently one welcomes with enthusiasm the proposal on the part of the 
Carnegie Institute to establish a meridian observatory in a suitable situa- 
tion in the southern hemisphere. Such an observatory, energetically 
worked, with due attention to all necessary precautions for the exclusion 
of systematic errors, would conduce more than anything else to remedy 
in some degree that want of balance of astronomical effort in the two 
hemispheres to which allusion has already been made. But in designing 
the programme of the work it should be borne in mind that the proper 
duty of the meridian instrument in the present day is no longer to 
determine the positions of all stars down to a given order of magnitude, 
but to determine the positions of stars which are geometrically best 
situated and of the most suitable magnitude for measurement on photo- 
graphic plates, and to connect these with the fundamental stars. For 
this purpose the working list of such an observatory should include only 
the fundamental stars and the stars which have been used as reference 
stars for the photographic plates. 
Such a task undertaken by the Carnegie Observatory, by the Cape, 
