202 
NATURE 
‘Ss 
[Fuly 2, 1885 
time, it is difficult to understand how in counting the 
longitudes, one should stop in the middle of the way, 
while in counting the time one goes the whole round of 
the day, reckoning the hours from 0 to 24, according to 
the decision of the Congress. 
Weare unwilling to believe that the advantage of not 
having to make any change in use and wont, not even to 
the extent of a few figures on English maps, was the 
ground of this decision on the part of the majority. 
This majority, for the rest, consisted in a preponderance 
of but three votes, and among the opposite voters or 
abstentionists we observe all the great Powers, with the 
exception of Russia. 
The question of a meridian being completely settled, 
the assembly had to address itself to the second part of 
its programme—that relating to universal time. 
The commercial and maritime relations so developed at 
the present day by the progress of the marineand telegraphy 
render the inconveniences attending a diversity of origins in 
horary measures more sensible every day. It has, there- 
fore, come to be desirable to establish a division of time 
having the same point of departure for the whole world. 
To attain this object the local time of a determined point 
is taken, and by a convention is made the universal time. 
In this system the influence of longitude is entirely 
eliminated. The same instant receives the same name 
all over the earth, and the acts of international life 
are dated in as close relation to each other in point of 
time as though they were acts transpiring all within the 
same town. As to the point to be chosen for giving the 
universal time, it is plain that it ought to be the same as 
that adopted for giving the departure of longitudes. The 
two systems cannot be separated. 
As a matter of course, this universal time cannot claim 
to take the place of local time, nor of so-called national 
time. The local time, which is the expression for each 
place, at least very approximately, of the course of natural 
phenomena, the eternal regulators of the acts of life, can 
never be displaced. In the case of certain arrangements, 
such as that of railways, for example, is it found highly 
convenient to extend the use of the local time of the 
capital to the whole country, when this latter has not a 
too considerable range of longitude. Such is the case in 
France. 
The Congress adopted in principle the establishment 
of a universal time defined in the manner I have just 
described. But, separating itself again on this point from 
the Congress of Rome, it assigned as the origin of the 
universal day the midnight of Greenwich, which, accord- 
ing to the proposals of the Washington Congress, should 
become the beginning of the day for international trans- 
actions all over the world. 
The divergence of resolutions adopted at Rome and 
Washington in reference to the origin of the international 
day brings clearly into view the inconveniences of the 
vexatious disagreement still actually existing between the 
origin of the astronomical day placed at midday, and that 
of the civil day placed at the preceding midnight. This 
inconvenience grows greater and greater in proportion as 
the ephemerides and astronomical studies extend. We 
therefore eagerly associated ourselves to the resolution 
expressed by the Congress relative to the unification of 
the two systems, by making the astronomical day com- 
mence at midnight, like the civil day. 
Astronomers will, we hope, understand that, being a far 
less numerous body, and much more conversant with 
these matters, it is on them that it devolves to make a 
slight sacrifice, so as to allow a progress very desirable 
at the present day to be effected. 
After the discussion of these various questions, the 
labours of the Congress approached their term; it was 
then that the French delegation made the proposal it had 
been charged to present—a proposal having reference to 
an important extension of the decimal system. 
The Congress of Washington, by its impoitance and by 
its object, which aimed definitively at the continuation of 
that great French work of unification and of progress in- 
augurated at the end of the last century, offered an alto- 
gether appropriate opportunity to ask for the world a new 
extension of those applications of the decimal system 
which constituted the whole merit and the whole success 
of our reform of weights and measures. 
This extension had relation to the measurement of 
angles and of time. 
At the date of the establishment of the metrical system 
the decimal division was, as is known, extended to the 
measure of angles and time. Numerous instruments 
were even constructed according to the new system. 
As far as time is concerned, the reform, introduced too 
drastically and without sufficient discretion, it may be 
said, clashed with too inveterate usages, and was rapidly 
abandoned; but in regard to the measure of angles, 
where the decimal division presents so many advantages, 
the reform held its ground much better, and has main- 
tained itself in certain practices to this day. Thus, for 
example, the division of the circumference into 400 ~ 
degrees was adopted from the beginning by Laplace, and 
it is currently employed in celestial mechanics. For the 
measurement of the arc of the meridian, whence the 
metre was derived, Delambre and Mechain availed them- 
selves of repeating circles divided into 400% Finally, 
in our days, Col. Perrier, Chief of the Geographical 
Service at our Ministry of War, makes use of instruments 
with decimal division, and at this moment calculates even 
logarithmic tables with eight decimals appropriated to 
this mode of division. 
It is above all, however, when it is required to execute 
long calculations on, angular measures that the decimal 
division presents intmense advantages. On this point 
nothing but unanimity may now be said to reign among 
learned men. 
The Conference of Rome, which assembled so many 
astronomers, geodesists, and eminent topographers—that 
is, just the men of most weight and having the greatest 
interest in the question—issued on this subject a resolution 
the high authority of which it is impossible to disregard. 
It is now, then, evident that the decimal system, which 
has already rendered so many services in the measure- 
ments of length, of volumes, and of weights, is called 
upon to render analogous services in the domain of 
angular magnitudes and of time. 
I am aware that this question of the decimal division 
has to contend with legitimate apprehensions, principally 
in reference to the measure of time. 
doing violence to secular customs and overturning conse- 
crated usages. On this aspect of the business I think we 
ought to be fully assured. The lessons of the past will be 
put to profit. It will be understood how it was for having 
endeavoured to push a reform beyond the due domain of 
science, and for having done violence to the habits of 
daily life, that disaster was experienced during the epoch 
of the Revolution. It is proper to resume the question, 
but it is proper to resume it with an appreciation of the 
limits which good sense and experience will always indi- 
cate to wise and experienced men. 
I think the character of the reform would be sufficiently 
indicated by saying that the question is principally to 
make a new effort towards the application of the decimal 
system in the scientific world. 
We met at first with a sufficiently warm opposition. 
The President was of opinion that the proposal should 
not be offered for discussion, but I have to acknowledge 
that he finally yielded very courteously, “out of defer- 
ence,” he said, “to the delegates of France, and because 
we are happy to do them honour in all things.” 
The majority decided that the proposal should be 
discussed. The French delegate then spoke, and the 
meeting passed to the definitive vote. The success was 
People are afraid of — 
citi i Marae ee 
_——— 
