44 
An examination of the above figures shows that the Fremantle 
tides are mainly controlled by the two diurnal tides, K and 0, and 
that the ordinary semi-diurnal lunar and solar ones are comparatively 
unimportant. This, of course, accounts for the tides being generally 
diurnal. It should be pointed out that the two tides, K and 0, are 
not exactly diurnal but nearly so, their periods being 23 hours 56 
minutes and 25 hours 49 minutes respectively. This gives one of 
the reasons for the irregularity of the Fremantle tides. 
With regard to Port Hedland, it will be seen that the mean lunar 
and the mean solar quite overshadow all the other tides, and hence 
the semi-diurnal character of these tides is not surprising. 
The diurnals K and 0 are next in importance but are so small 
that they only have a chance of making their presence felt about the 
time of first and last quarter of the moon and are only partially 
successful. 
It has only been possible to analyse the records for this one 
year, for the simple reason that the services of the tide-computer 
have been dispensed with, and consequently the work of collecting 
the hourly readings and performing the preliminary computations 
has come to a standstill. This is a very great pity and should be 
remedied as soon as possible. The subsequent year’s records are 
urgently awaiting compilation and in addition observations should 
be extended to other ports, in the tropics at all events, in order that 
tide tables from them should be available to shipping. 
