Grusp—Time Signals. 37 
VI. 
ON THE CORRECTION OF ERRORS IN THE DISTRIBUTION 
OF TIME SIGNALS. By SIR HOWARD GRUBB, F.B.S., 
Vice-President, Royal Dublin Society. (Puares IV. and V.) 
[Read Novemser 16; Received for Publication Novemser 21, 1898 ; 
Published Marcu 25, 1899.] 
Havine had occasion lately to inquire into the merits of the various 
existing systems of synchronizing clocks, and to report on the best 
arrangements to be made suitable for a large Municipal Institu- 
tion in one of the larger English towns, I have thought that it 
might be interesting to the Royal Dublin Society if I placed be- 
fore them the results of my inquiries and the conclusions at which 
I have arrived, more especially as the conditions existing in the 
Institution referred to are, in many ways, very similar to those in 
the Royal Dublin Society, though on a larger scale. 
It is hardly necessary, at this period of the nineteenth century, 
to enlarge on the importance of having correct time available; and 
the Royal Dublin Society recognised this many years ago by estab- 
lishing a system of synchronized clocks in Dublin, controlled from 
a central clock in this house, which clock was itself checked by a 
daily signal from either Greenwich or Dunsink. 
The controlling of the outside clocks throughout the town was 
effected by sympathetic pendulums of the “ Ritchie ” type, and the 
system worked well at first; but in time, as the telegraph and tele- 
phone wires accumulated in the city, the induction produced in our 
wires from the strong currents in the adjacent wires caused such 
serious trouble and irregularities as necessitated the abandonment 
of the system. This has been the case also in many other towns. 
The conditions present in the Institution on which I have lately 
had to report are, as I said, somewhat similar to that of the Royal 
Dublin Society (not taking into account any outside clocks); that is 
to say, itis a building unconnected with any Observatory, and unsuit- 
able for the erection of transit instruments, and therefore has to 
depend ultimately on a daily signal from Greenwich. It contains 
some 200 rooms, each requiring a clock face which it is desirable 
