AN AUSTRALIAN STUDY OF AMERICAN FORESTRY. 11] 
In well-surveyed country it amounts only to a retracement of existing land 
lines and the reblazing of at least every second “section” line. In poorly 
surveyed areas, it consists of establishing a gridiron of traverses in cardinal 
directions. In unsurveyed lands, it has to furnish a skeleton of traverses along 
the ridges and creeks. 
The object is “to criss-cross each project with a series of more or less 
parallel lines and profiles, not over two miles apart, preferably one mile in 
timber reconnaissance and land classification and not over three miles in 
grazing reconnaissances. The endéavour is to parcel the area out into forty- 
acre blocks. 
Transit and stadia are most usually employed in secondary control, a 
light mountain transit with stadia hairs and solar attachment being used. The 
crew comprises four men, viz., an instrument man in charge, a recorder and 
computer, a rodman, and an axeman. 
Where the cost of brushing for stadia sighting is heavier than that of the: 
necessary chainmen, transit and chain is the method adopted. 
In cases where the area is not to be “stripped ” owing to its unimportance 
in the forest scheme, the Johnson plane-table and an 18-inch telescopic alidade 
and stadia rod are employed. The positions are located by triangulation 
and the details are sketched in at the same time. 
Where speed is essential a three man crew with chain and compass and 
new Abney are employed. 
This year (1916) District No. 1 is trying out the Solar compass and chain 
method, with the idea of overcoming local magnetic attraction, and achieving 
a high rate of speed. 
Lines are blazed, and permanent monuments established at intervals of 
about a mile. A guide stake is set up at every ten chain distance to indicate 
the starting and closing points for strip surveys. Each north and south line 
is lettered, and each strip station is marked with the letter of the traverse, 
the number of chains from the south end of the forest, and the elevations. 
The strips are numbered consecutively. 
The limit of error with transit and stadia is set at 4 feet horizontally and 
1 foot vertically per 1,000 feet of distance. With the compass and chain, 
however, two or three times this error is permitted. 
Before a traverse is used as the strip starting base, it is plotted in ink 
on the camp map and the closing error distributed by graphic adjustment. 
Tertiary control is the actual work of clothing the secondary control frame- 
work with the topographic detail. It is the “ intensive reconnaissance.” 
Ordinarily it is accomplished by “strip surveys.” Exceptionally, and 
where unimportant patches occur, it is carried out by plane-table triangulation 
and traverse. 
On timber reconnaissance and land classification, the strips are placed 
every ten or twenty chains; in broad grazing reconnaissance they may be as 
much as forty chains apart. 
The organisation of the assessment party depends on the class of recon- 
naissance to be undertaken. 
The officer-in-charge is generally an assessor of ability and experience. 
He is appointed by the district forester, but is responsible directly to the 
forest supervisor. 
