be included, resolved itself into the
equivalent question, What should be the length of time during which the
plates were exposed? Then, again, the question, What observatories should
take part in the work? became simply this: What observatories could
afford to acquire the instruments of this new pattern and get other funds
for carrying out the work specified? It was ultimately found that eighteen
observatories were able to obtain the apparatus and funds, though
unfortunately three of the eighteen have since found it impossible to
proceed. The following is the original list, and in brackets are added the
names of three other observatories which in 1900 undertook to fill the
places of the defaulters.

OBSERVATORIES CO-OPERATING FOR THE ASTROGRAPHIC CHART.

+----------------------+------------+----------+
| Observatory. | Zones of | Number |
| |Declination.|of Plates.|
+----------------------+------------+----------+
|Greenwich |+90 deg. to +65 deg.| 1149 |
|Rome |+64 deg. " +55 deg.| 1140 |
|Catania |+54 deg. " +47 deg.| 1008 |
|Helsingfors |+46 deg. " +40 deg.| 1008 |
|Potsdam |+39 deg. " +32 deg.| 1232 |
|Oxford |+31 deg. " +25 deg.| 1180 |
|Paris |+24 deg. " +18 deg.| 1260 |
|Bordeaux |+17 deg. " +11 deg.| 1260 |
|Toulouse |+10 deg. " + 5 deg.| 1080 |
|Algiers |+ 4 deg. " - 2 deg.| 1260 |
|San Fernando |- 3 deg. " - 9 deg.| 1260 |
|Tacubaya |-10 deg. " -16 deg.| 1260 |
|Santiago (Monte Video)|-17 deg. " -23 deg.| 1260 |
|La Plata (Cordoba) |-24 deg. " -31 deg.| 1360 |
|Rio (Perth, Australia)|-32 deg. " -40 deg.| 1376 |
|Cape of Good Hope |-41 deg. " -51 deg.| 1512 |
|Sydney |-52 deg. " -64 deg.| 1400 |
|Melbourne |-65 deg. " -90 deg.| 1149 |
+----------------------+------------+----------+

[Sidenote: Sky covered twice.]

In the list is also shown the total number of plates that were to be taken
by each observatory. When once the size of the plates had been settled,
it was a straightforward matter to divide up the sky into the proper
number of regions necessary to cover it completely, not only without gaps
between the plates, but with actually a small o