NA RGRE 
313 
THURSDAY, AUGUST 6, 1885 
A POSSIBLE WINDFALL FOR SCIENCE 
N arecent article we referred to the question of the 
amalgamation, so to speak, of the astronomical and 
civil day, in connection with the introduction of world 
time or prime meridian time, suggested by the Wash- 
ington Conference. We pointed out that there were 
various opinions touching the time at which the change 
should be made, but that the concensus in its favour is so 
strong that it is certain to be made some time or 
another. 
Our contemporary Sczence has recently called attention 
to a point which, if carried out, will make the work com- 
plete at an annual saving on the outlay of the present of | 
something like 20,000/. 
How is this to come about? In this wise. Let us 
suppose four nations A, B, C, or D, who each support a 
national observatory chiefly for the benefit of its Marine. 
This benefit consists in telling the mariners at what 
instant, according to the time shown by the clocks of 
A, B, C, or D, any celestial event, useful to him for 
determining his place at sea, will happen. 
Let four ships, one of them representing each one 
nation, be within a cable’s length of each other in the 
middle of the Pacific when the time comes for making an 
observation to determine position. Four books will be 
used, the production of which has been enormously 
costly, as each consists almost entirely of figures which 
depend upon elaborate calculations. 
If the books are rightly calculated and the captains 
are skilful, of course the same position will come out in 
each case, 
Evidently this work has been done four times over, and it 
is equally obvious that the result should have come out the 
same if the position had been determined properly on 
either ship from data supplied by either book. Why is 
this? Because our nations, though they have accepted 
in common the art of printing, the art of binding of 
printed pages together to form a book, and Arabic 
numerals, have not accepted a common time. 
To come down from our generalities the four ships 
might have belonged to Germany, France, the United 
States, and Great Britain, and the four books might have 
been the Berliner Jahrbuch, the Connaissance des Tenips, 
the American Ephemeris, and the Nautical Almanac. 
Sympathetically with these four books, at least three 
different times might have been indicated by the chrono- 
meters. And here lies the point. Aecawse these chrono- 
meters show the time at Paris, or Berlin, or London 
therefore the computations of each celestial event, using 
the same data, employing ‘the same processes, have been 
undertaken by each nation. 
But even this is not all. We have said that at least 
three different times might have been indicated, and on 
our supposition only three times would have been indi- 
cated, because the U.S. Marine actually use Greenwich 
time. 
Now it is clear that the general introduction of world 
time or prime meridian time, with the idea of which we 
are beginning to be familiar, will do for time what the 
VOL. xxxIt.—No. 823 
introduction of the Arabic numeral did for numbers—it 
will denationalise and generalise it whenever necessary ; 
and each observatory, sooner or later, is certain to have 
a clock showing the prime meridian time of the earth as 
it has one already of the skies, and when this comes about 
it will be to the general advantage for all to deal with the 
common time for purposes common to the planet. 
Now among these what can be imagined more planetary 
than those with which the mariner has to do, and if this 
be so why shall there not be one unique planetary 
ephemeris. 
From the abstract point of view more than one ephe- 
meris cannot be defended, though it may be pardoned if, 
as Scfence suggests, the nations, to save their amour 
propre, must have ephemerides for their several meridians 
“much the same as all patent medicine firms and pill 
vendors feel the need of an almanac and calendar for the 
conservation of individual interests; it saves themselves 
and their patrons the indignity of referring to somebody 
else’s almanac, and advertises the fact that they are 
enterprising enough to have one.” 
We cannot believe that the feeling characterised above, 
though it exists, would stand in the way of such a vast 
saving of labour and such a general improvement as 
might be brought about by an International Ephemeris, 
| provided the question were well ventilated and wisely 
discussed by a congress summoned ad hoc. 
Science writes :— 
On this point 
“Tt is certain that the deliberations of such a congress 
could not fail to advise governmental co-operation in the 
preparation of the nautical almanacs now existing, national 
pride aside, and this might be done ina multitude of ways, 
most prominently in the case of the preparation of the 
data relating to the moon. Take, for example, the hourly 
lunar ephemeris and the lunar distances as printed each 
year in the British Nautical Almanac and the American 
Ephemerts. These data occupy about one-third of the 
entire number of pages of each of these publications ; 
they are now prepared independently by the two offices, 
but are, when printed, substantially identical in both ; 
and, further, the work being done at about the same time 
in the two countries, the results of the one do not serve 
any sufficient purpose as a check upon the accuracy of 
the other. The cost of this part of the almanac alone to 
each nation amounts to several thousand dollars annually, 
—an amount which might be reduced one-half by the 
preparation of these data conjointly, to say nothing of 
other immediate and favourable results which might be 
secured by such co-operation. 
* The wisest conservatism would appear to suggest the 
annual publication by the nations conjointly of a single 
volume of astronomical predictions, which, in addition to ° 
other improvements, should combine all those desirable 
features not dependent upon individual meridians, and 
which in some degree characterise all the astronomical 
ephemerides of the several Governments. The contents 
and arrangement of the articles of such an ephemeris 
could only be determined by an international conference. 
While this may be little better than mere speculation, any 
one who has the four principal ephemerides in constant 
use will readily recognise how small a portion of each is 
employed, and, with extended interpolation-tables, how 
little the inconvenience of using the ideal ephemeris solely 
would be.” 
It is sufficiently obvious that this enormous simpli- 
fication and improvement must come about some time 
or the other, and it is to be hoped that no very long 
time will be allowed to elapse before some fsovernment 
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