xi Appendix. 
To obtain as speedily as possible a correct diagram’ of the triangulation 
has evidently been felt highly desirable in England as well as here, but the 
method recommended by General Frome (page 182) can only give a very 
rough approximation—one indeed so rough that I should be inclined to call 
it useless. In order to keep the plot of topographical work well forward, I 
suppose every surveyor engaged in trigonometrical work has felt the neces- 
sity for this diagram. 
The method pursued by myself is to keep a series of separate calcula- 
tions, which I term “rough solutions and reductions,” some of which I 
exhibit in connection with a triangulation now in progress. These solutions 
are made as the triangulation proceeds, most frequently from two observed 
angles, only no attempt being made to eliminate errors of observation or to 
obtain mean results. These reductions, however, enable the stations to be 
accurately laid down on paper at once, leaving the ultimate calculations, 
with all corrections, mean results, etc., applied, to follow in the rear. 
In this manner the plot of topographical work is kept almost as far on 
as the triangulation itself, and that in a manner which, I think, all sur- 
veyors will agree, is very far in advance of the methods apparently sanc- 
tioned in England. 
As regards the plotting of detail work, the best method apparently 
known in England, and recommended by General Frome (note page 50) 
for plotting traverses is by using a card-board protractor, with the centre cut 
out; or, for surveys on a large scale, the circular brass protractor, with 
vernier, is recommended, as being more minutely accurate, each line being 
added from the plotting of the preceding one. ‘Both these methods have 
been tried here, and thrown aside many years ago as unsatisfactory, inex- 
peditious, and incorrect in practice. 
Sometimes on a detail, or particularly a large topographical survey, 
there are not less than several thousand bearings to be protracted, and it 
is of the greatest importance that a method should be used, combining 
accuracy and expedition. 
The following is the method in use by myself and most other colonial 
surveyors, I believe :— 
The meridian and perpendicular of the initial station being first laid 
down on the sheet, lines parallel to these are carefully transferred, cutting 
each other about the centre of the sheet, and a large protraction is laid 
with a fine needle point on the sheet itself. 
This may be done with great accuracy by means of a heavy brass ruler, 
with cylinders of large diameter, and a boxwood scale from the table of 
natural sines and cosines, using parts of each of the four lines in the direc- 
tion of the cardinal points alternately as sines and cosines for each arc, 
_ differing one degree of the circle. 
