178 The N.Z. Journal of Science and Technology. [May 
Fig. 19 is the weather map for the 22nd May, 1914. By this date all 
the “ lows ” had passed to the eastward, and an anticyclone was approach¬ 
ing, bringing an improvement in weather conditions. 
Fig. 20 is a chart combining the isobars of Australia and New Zealand 
for the 18th May, 1914, and includes all the atmospheric systems shown 
separately in figs. 15 to 19. The centre of each system is marked with 
a letter—viz., A to D —and the same systems are similarly marked in figs. 15 
to 19. By comparing each of the systems in fig. 20 with the corresponding 
ones in the other charts we are able to follow their respective movements. 
The whole system moves forward in the same way as it would were we to 
take a chart of the isobars only and move it from west to east over a fixed 
map of the country. 
There are therefore two movements to account for- first, the circulation 
of the air in the system itself, and, secondly, the translation of the whole 
system from west to east. If we can anticipate the latter correctly, then 
the direction of the wind becomes a comparatively easy matter to decide. 
Just in the same way as eddies in a stream are carried along by the motion 
of the stream, so the cyclone and the anticyclone, which are huge atmo¬ 
spheric eddies, are carried bodily forward by the prevailing motion of the 
air, which in these latitudes is from west to east. 
Cyclone-tracks . 
Most of the cyclonic systems which originate in the tropics and eventually 
come within effective distance of these Islands take certain fairly definite 
routes. Fig. 21 shows the approximate paths of several typical cyclones, 
and these are the directions usually taken. The centre rarely passes directly 
over the land, especially where mountain-ranges intervene, and tends to 
follow the coast-line. They thus frequently pass through Cook Strait, 
and have often moved down the west coast of both Islands, striking east¬ 
ward only when they have reached the southern extremity of New Zealand. 
Concluding Remarks. 
From what has been written it will be seen how indispensable the weather 
chart is in forecasting, and how such a chart cannot be quickly and 
accurately compiled except at a central bureau in direct telegraphic com¬ 
munication with a chain of observers. Yet in nearly all countries individuals 
may be found who, either for private gain, popularity, or maybe as a hobby, 
issue forecasts, and unfortunately they are sometimes encouraged to do 
so by newspapers. They are certainly to be admired for their boldness in 
undertaking a work which a responsible meteorologist would hardly dare do 
unless he had at hand all the data available only at an organized weather 
bureau. 
A general knowledge of the types and movements of storms should, 
however, be helpful to those anxious to form judgments of coming weather- 
changes, and with this object in view farmers and shipping men particularly 
should be encouraged to study more frequently the official weather reports 
and forecasts issued daily. 
From the weather map it is possible to make predictions for from thirty- 
six to forty-eight hours, and occasionally a general idea may be obtained 
of the weather to be expected over a period of five or six days. It is, 
generally speaking, impossible to make a forecast for a longer period, and 
investigations have shown that under the present development of meteoro¬ 
logical science long-range forecasting is impracticable. 
