Eichardson. — On the Survey System. 495 



standard is a mean between our extremes. As all our stan- 

 dards disagree, it is obvious that nine out of the ten must be 

 wrong, and that probably all ten are ; also that these discrep- 

 ancies must introduce a constant error through all work based 

 upon them, apart from the inherent error of the work itself. 



I have recently brought this matter under the notice of 

 the Government, which will, I have no doubt, take steps to 

 lay down a standard chain-length for the colony with the 

 highest degree of accuracy obtainable ; and, once a standard is 

 determined, its exact duplication by means of instruments of 

 precision is comparatively simple. The best appliances we 

 possess are two Imperial-standard- yard measures, which do not 

 agree with each other ; but, even if they had been reliable, we 

 have not the requisite apparatus to enable us to utilise them. 

 It is clearly necessary to lay down a correct standard for the 

 colony, and, as New South Wales and Victoria each possess a 

 standard chain laid down with extreme care, I should propose 

 to compare one with the other, and, if the coincidences war- 

 ranted it, to establish our standard of length from theirs. The 

 crypt below the new parliamentary library would be very 

 suitable for its permanent resting-place. 



The Brisbane standard chain (1890), which was laid down 

 with a 10 ft. octagonal steel bar floating m mercury, has been 

 tested with that of Sydney (1899) and with the United States 

 American standard (1891 and 1899), the coincidences being 

 within T |o in. 



The next step should be to bring our triangulations into 

 harmony with the standard, and, consequently, with each 

 other. Official objection is sure to be raised to thus elimi- 

 nating error, on the ground of confusion, but such an objection 

 will not hold water — the confusion exists, and the differences 

 arising through its removal should not exceed the official allow- 

 ance of error, and can in no way interfere with or affect title. 



Having overcome the difficulty of determining a unit of 

 absolute length, the question would arise how best to bring 

 all important measurements into terms with it, and to do this 

 within fine limits of error the only certain and economical 

 plan is to give further effect to our survey system (already 

 described) and carry out the long-postponed primary triangu- 

 lation. This can be done with marvellous precision, and yet 

 at a smaller cost than would have been possible a few years 

 ago. Many things contribute to this result, but chiefly the 

 modern methods of measuring base-lines and the fact that 

 the country is now opened and its topography completed. 



Looking to the necessity for a primary triangulation for 

 our own purposes, and also to the wider interests of science, I 

 should like to see it carried out as a geodetic work of refine- 

 ment and applied to the measurement of an arc of meridian. 



