EDITORIAL. 
that a shaft, should be sunk to the depth of 12 miles. The estimated 
cost was set down at £5,000,000, and the time required for the work 
85 years. Since then experiments have shown that the scheme is prac- 
ticable. At Lardarello, in Italy, bore holes have already been made 
which discharge large volumes of high-pressure steam, and this is being 
utilized to generate about 10,000 h.p. by means of turbines. An alterna- 
tive proposal is made that further attention should be given to the 
development of water power, and The Hngineer, commenting upon this 
idea, writes:—“ Living on an island against which the waves of the 
Atlantic and the North Sea for ever beat, and in which the variations 
of the tides are in many places very considerable, we see continually 
around us, nowhere far removed from the centres at which it would be 
used, manifestation of a power that exceeds the widest limits of our future 
needs. Difficult as are the problems connected with the development of 
wave and tidal power, we are convinced that they are not insoluble, and 
that it needs but the concentration of great inventors, coupled with the 
courage of great financiers, to open to this kingdom a source of power 
that will leave the heat engine behind, just as the heat engine itself has 
displaced the labour of animals and the variable force of the wind.” 
AGRICULTURAL TRACTORS. 
A wide diversity of opinion still exists in Australia in regard to the 
importance of the tractor for farming operations. Tractors are grad- 
ually growing in favour, but they are used on a very small scale in 
comparison with horse teams. On the other hand, in the United States 
and in Great Britain tractors are being widely adopted. In Great 
Britain trials are frequent and exacting, and according to official reports 
these new implements are as a general rule doing what is expected of 
them. No general purpose tractor, however, has yet been invented. 
Nor is it considered likely that such a tractor will ever be perfected. 
For road work the machine must be heavy to enable it to get a grip on a 
hard and smooth surface, but weight is a disadvantage on the land, 
where the grip can be obtained by means of cones or spuds on the wheels. 
During the war, when it was essential that a very large increase should 
be made in the acreage under cultivation, the British Government, 
because of the inability to secure horses, took steps to purchase every 
tractor of almost any make that was available. Naturally the initial 
difficulties in getting them to work were enormous. Inherent defects in 
many of the machines, the scarcity of trained engineers, and the absence 
of spare parts were only a few of the handicaps. Yet the tractors 
solved the food problem. 
ADVENT OF THE TRACTOR IN GREAT BRITAIN. 
Although the whole project was one huge experiment, and its cost was 
justified only by the serionsness of the food situation, yet it is ‘con- 
sidered likely that the experience gained from this wholesale employment 
of mechanical traction will compensate for the outlay. The Journal 
of the Royal Agricultural Society of England, in commenting upon the 
work, states that “ the experiment has almost revolutionized our Enelish 
methods of farming, and in no other way could mechanical power have 
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