ConnELL.—On New Zealand Surveys. xli 
Taking a radius of ten inches, we have thus a protractor twenty inches 
in diameter, divided accurately to each degree of the circle, and the degrees 
may then with the scale be subdivided to thirty or even fifteen minutes, 
leaving intermediate proportions to be estimated by the eye on applying the 
brass ruler for the purpose of protracting a bearing. 
As a fine needle only is used to mark the points, the protraction is 
scarcely visible, except on close inspection, on the completion of the map, 
after pencil marks have been rubbed out, and yet it may at any time be 
resuscitated for the purpose of testing the plotting, if necessary. I exhibit 
a plot sheet of topographical work in progress, with protraction twenty 
inches in diameter thus constructed.* 
Whilst the use of protractors of large diameter, carefully laid down 
in the plot sheet itself, enables us to lay down bearings, however numerous, 
correctly, it must be borne in mind that all traverse points of the detail 
survey are, under the Otago system, plotted altogether independently of any 
protraction whatever, directly from the traverse tables, and furnish reliable 
points from which the various bearings may be accurately protracted by 
the method I have referred to. 
I venture to say that it is quite impossible to construct a large map 
with a good deal of traverse work in it, correctly, by either of the methods 
recommended by General Frome in the note referred to. 
Before bringing this paper to a close, by referring shortly to the subject 
of the revision of old surveys, I think it will be appropriate that I should 
say a few words as to the reasons which have induced me, in referring to 
the Otago system, to say little or nothing about the work which had to be 
done ere it was possible to institute the Minor Triangulation on the satisfac- 
tory basis upon which that work was begun in this Province. My reason 
for so doing has been because I conceive we have to-night amongst us 
gentlemen who can handle that branch of the subject very much more ably 
than I could hope to do, gentlemen who initiated and carried on the astro- 
nomical and, as we call it, the standard part of the work. 
_ I trust these gentlemen will supplement my dry and somewhat common- 
place paper on the immediately practical branches of colonial survey, by 
some account of their more interesting and more scientific labours. 
I proceed, in conclusion, to consider shortly the subject of proposed 
revision of surveys already in existence, but pervaded confessedly in some 
parts of the Colony with many and considerable blunders. 
* For the suggestion of the above method of constructing a protraction, which I find 
superior to every other I had previously tried, I was indebted to my late assistant, Mr. 
Begg, who gave promise of being an ornament to the profession, but who is now unfor- 
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