145^ 



blocks, and with which to connect the various town surveys 

 required from time to time under the Real Property Act. 



(7.) The surveys are made to independent magnetic 

 meridians, the bearings of the initial line in each survey being 

 derived from the compass or needle-reading. 



(8.) The office plans and compilations are constructed 

 entirely upon the " building-up " system, without the check 

 afforded by the connection of surveys with accurately deter- 

 mined trigonometrical stations. 



With regard to sub-section (7) above, it is perhaps right to 

 note that an independent or isolated survey, executed under 

 the method therein indicated, may be extremely accurate in 

 itself, that is within its own boundaries; but it is obvious that 

 the surveys, effected by a number of surveyors, working to 

 their own independent compass meridians, which, even apart 

 from special local attraction, are certain to vary considerably — • 

 cannot be properly compared as to boundaries and relative 

 positions, and are therefore " floating " to an extent which is 

 unknown and practically unlimited. 



With respect to sub-section (5), it is not unreasonable to 

 assume that where a certain limit of error is recognised, a 

 considerable proportion of the surveys, especially in rough 

 country, will come nearly up to that limit. The limit of error 

 formerly allowed in Tasmania, and probably still recognised, 

 was 32 links in the mile (1 in 250), a limit three times greater 

 than a fair allowance. A limit of error of 8 links in the mile 

 (1 in 1,000) for ordinary sectional work, is regarded as a 

 maximum allowance under any system professing to give 

 reasonably accurate results. 



The statements made by Mr. Calder in the letter above 

 referred to, may be fairly summarised as follows : — 



1. That Tasmania is so densely wooded and rugged that it 

 is impossible to adopt a really accurate and scientific system 

 of survey, and its peculiarities " will for ever enforce peculiar 

 modes of surveying." 



2. That the setting aside of the compass meridian in favour 

 of the True Meridian would, on account of obstructions, involve 

 a " delay of several hours a day in the frequent determination 

 of the True Meridian, which would be required of the surveyor, 

 in many districts, every time the boundary line ran into a tree 

 too massive to be removed." 



3. That " trees are not to be passed by without liability to 

 error; " and that he has found in practice no " better method 

 of mastering the difficulty than that of observing the compass 

 bearing of the line at the point of obstruction, and then 

 proceeding in the same direction from its opposite side. By 

 this process the error is not an increasing one, and though 



