(OCR from original text)

Eiffel   Tower   Wireless   Time Signals.

   IT may interest a number of readers of NATURE to
know that the Eiffel tower is at present sending out
two additionai sets of "scientific" time=signals. The
scientific signals  are  arranged  as a time-vernier,
gaining about one beat in fifty. They have hitherto
been  sent at 11.3o p.m. G.M.T., followed  at 11.45,
after  the ordinary  time-signal is  concluded, by
numbers which give the moment of the first and the
last signa] of the set, according to the standard c|ock
of the Observatory of Paris.  A comparison can thus
be made with the introduction of a very small error,
often   not exceeding one-fiftieth of a second. These
va|uable   signals have suffered from   two  awkward
features: In summer time   they  are inconveniently
late, and  the purring   or snoring note (ronflee) on
which they are sent is much obscured by atmospherics
when the Iatter are bad. so that sometimes one failed
to pick up the identification breaks which occur at the
end of every sixty beats.
   In   addition to the old series, which remain un-
changed. two new series are now being sent:  these
are  on  wave-length  2600 metres  and  a  high
musical note that cannot be confused with atmo-
spherics.   Otherwise they are the same as the original
-300 dots, the 60th, 120th, 180th and 240th being
suppressed. They   are   sent: (1)  at   10.30   a.m.
G.M.T., the comparison numbers giving Paris time
following after completion  of  the  10.45 ordinary
signa|:   and   (2)   at 11 p.m. G. M.T., the  com-
parison  numbers  being  sent  after the  11:45 ordinary
signal, along with those which refer to the old 11.30
signal, the two rferences being distinguished by the
1etters  ML  (musicale)  and  RF  (ronflee) respectively.
The new series are beautifully clear. and ought to be
of great service to those who require arcurate time.
                                   R. A.  SIMPSON.
  Royal Observatory, Edlnburgh. April 17.