1918.] The N.Z Journal of Science and Technology. 
233 
The choice of 11 h. 30 m. was determined in the first place because it is a good 
mean for the whole country,* and secondly because of the simplicity of this number ; 
for it must be remembered that it was not until about fifteen years later that the idea 
of standard times in other parts of the world, based on exact hourly differences from 
Greenwich, began to be adopted. Against the adoption of a difference of either 11 or 
12 hours for New Zealand it was argued that either of these would involve considerable 
departure from the mean solar time. Recent considerations, however, have strengthened 
the opinion that the adoption of a standard time in advance of the solar time is a real 
advantage to the community, especially in countries in which there is not an extreme 
variation in the lengths of the day in summer and winter. This is illustrated by the fact 
that South Africa and South Australia have each adopted a standard time in advance 
of the solar time for by far the greater part of the country. New Zealand is so happily 
situated that it is possible, by adopting a standard time 12 hours in advance of Green¬ 
wich, to secure the advantages of an advanced time and also the greatest possible 
degree of simplicity in relation to Greenwich. 
The subject was discussed in a paper on “ Day light -saving ” read before the Wel¬ 
lington Philosophical Society by Mr. C. W. Adams on the 27th September, 191(1, and at 
the Council meeting held on the 30th November, 1916, the following resolution was 
carried unanimously : “ The Council of the Wellington Philosophical Society resolved to 
urge upon the Government the desirability of making New Zealand mean time exactly 
12 hours in advance of Greenwich mean time.” 
The mean time in use in New Zealand is exactly 11 h. 30 m. in advance of Greenwich 
mean time, and corresponds to the meridian 172° 30' east of Greenwich. The change 
to 12 h. in advance of Greenwich mean time would be made by putting the clock forward 
one half-hour, once for all. 
The following are some of the grounds of the Council’s support of the proposal, 
and they show the advantages and benefits to be gained by giving effect to the 
resolution :— 
1. An immediate consequence of the proposal would be a saving in all lighting of 
half an hour daily. This would materially reduce the maximum power demand on 
electric and gas lighting and power plants in the winter-time. Prom a power-supply 
point of view the alteration is highly desirable, as the overlapping power and lighting 
load from 4.30 to 5 p.m. in winter makes a great and sudden demand on the power 
plant; and ultimately the alteration would lead to a reduction of capital expenditure, 
for it would not then be necessary to provide for the overlapping load at the power- • 
station. 
2. Conformity with the International Time Agreement that mean time should be 
an exact number of hours different from Greenwich mean time—viz., 12 h., instead of 
11 h. 30 m. as at present. 
3. The conversion of time between the United Kingdom and New Zealand would 
be made in the simplest possible manner. For example, in all commercial uses it would 
only be necessary to exchange “ a.m.” for “ p.m.,” and vice versa : thus if a cable left 
London at 3 p.m. on January 1 the equivalent time in New Zealand would be 3 a.m. 
on January 2. The system proposed of simply changing “ a.m.” for “ p.m.,” and 
vice versa, does not offer the same difficulties or chances of error as the adding or 
deducting of 11 h. 30 m., particularly when one has to consider whether the correction 
has to be added or subtracted. 
4. For all astronomical and nautical calculations the benefits of such a simple method 
of converting time are obvious, and have been practically recognized at the Observatory, 
where all the mean-time clocks are kept 30 m. fast on New Zealand mean time— i.e., 
12 h. fast on Greenwich mean time. The time signals at Wellington, Auckland, Lyttel¬ 
ton, and elsewhere are always given at exact hours of Greenwich mean time. This 
practical trial of the method has received the strong support of nautical officers, and 
if the change advocated is given effect to, then these time signals will be directfy avail¬ 
able for the rest of the community. 
5. Precedents for the alteration are to be found in the case of— 
(a.) South Africa^ which from 1892 to 1903 used a time 1 h. 30 m. fast on Greenwich 
mean time. In 1903 the time was altered to an exact number of hours 
fast on Greenwich mean time—viz., 2 h.—when all clocks were put on half 
an hour. 
( b .) Ireland, where Greenwich mean time has recently been adopted, and the clocks 
were put on 25 minutes. 
* This corresponds to the meridian of 172£° E. of Greenwich. New Zealand lies between the 
longitudes 178° 36' and 166° 26', the mean of which is 172° 31'. The meridian which has an equal area 
of land on each side of it has been given as 172° 49'. On the other hand, the mean longitude for the 
population is probably about 174°. 
