AGATHIS AUSTRALIS. 151 
Many streams in kauri districts do not contain sufficient water to float the 
logs, so that it is necessary either to increase the supply of water, or to construct 
a tramway to deep water or to the mill direct. The depth of water is increased 
by the construction of one or more dams to enable a large quantity of water to 
be stored at high levels: taking advantage of the first ‘‘ fresh’? caused by con- 
tinuous rain, the sluices of the dams are opened, and the logs, which are often 
piled high in the bed of the stream, are ‘‘driven” to the booms by the volume 
of water suddenly liberated. The booms are formed by large logs secured to 
each other and to the bank by strong chains: they often enclose an area of 
several acres, which, after a successful ‘‘ drive,’ 1s crowded with thousands of 
logs. The.construction of dams often involves a vast amount of labour in exca- 
vating, puddling, and construction: the outlay varies from £250 to £1,000. 
Large sums of money are also spent in removing boulders and snags from the 
beds of creeks, and in rounding sharp angles, &c. In many cases the logs 
are conveyed to the mill by tramways, especially when the mill is situated in the 
neighbourhood of the forest: these tramways are often of a substantial character, 
and involve a much heavier outlay than tramways in the extreme southern 
districts, owing to the broken character of the country, which often renders it 
necessary to excavate deep cuttings and construct embankments. They are 
worked by horse-power or steam. On the Northern Wairoa immense rafts of 
logs obtained from the banks of its numerous tributaries are towed to the saw- 
mill by steam-tugs. 
In back-country where the mills depend upon driving for the supply of logs, 
a protracted period of dry weather, or a scanty rainfall, may prevent conversion 
being carried on for several months, the entire plant and machinery being 
rendered unproductive for that period, although thousands of logs may be lying 
in the dry bed of the stream. Excessive rain, causing high floods, forms another 
source of loss, the logs being brought down with such impetuosity that the booms 
are broken, and hundreds of logs are swept out to sea. 
As a general rule the trees are felled, cross-cut, and the logs rolled_into the 
stream by contract, the cost varying from Is. to 2s. per 100 superficial feet, 
according to situation: higher prices are occasionally paid, and in some situa- 
tions the work is done by day labour. Although kauri timber is remarkably 
sound, it often becomes greatly damaged in transit over broken country, or when 
driven along the beds of rocky creeks ; not infrequently the logs are rolled over 
cliffs 20ft. to 50ft. high into the stream below: treatment of this kind necessarily 
results in an enormous amount of waste, the ends of the logs being split or 
spalted to a great extent, so that the discrepancy between the original measure- 
ment of the logs when rolled into the creek and the converted timber is often very 
ereat indeed, and cannot be estimated at less than 30 per cent., while in extreme 
cases it will range from 40 to 45 or even 50 per cent. As a general rule logs 
obtained in the Wairoa basin, unless growing very far back from tidal water, are 
less injured during flotation than logs obtained in the Hokianga district and 
on the Cape Colville Peninsula, the beds of the streams being less rocky in the 
former district than in either of the latter. 
- The kauri saw-mills are by far the best in New Zealand, and are not sur- 
passed by any mills south of the equator: some of the largest are able to con- 
vert from 8,000,000 to 10,000,000 superficial feet per annum. The machinery 
is generally of the best, and is specially adapted to the conversion of large timber. 
A vertical frame-saw for breakine-down work 1s invariably in use: in one or 
two instances horizontal frame-saws are employed for this purpose, but the 
