BY W. A. ‘TULLY, £SQ.; B:A., F.R.G.S., ETC. 131 
much that it was surrounded by hills, which permitted of 
stations being readily obtained for extending the triangulation. 
All the preparations having been made, and the plant brought 
to the ground, the measurement was commenced on August 
24th, 1883, under the superintendence of Mr. District Surveyor 
McDowall, assisted by Mr. R. Hoggan. The base was divided 
into ten sections: the six central ones averaging nearly a mile, 
and the two others at each end being nearly half-a-mile 
long. The terminal points of these sections were marked by 
stones sunk into the ground and set in concrete. Hach stone 
had a metal plug, upon which a small mark was made denoting 
the terminal point of the section. The tapes used on the survey 
were about half-an-inch wide, and little more than a hundredth 
of an inch thick. The one hundred feet lengths are denoted by 
minute dots, or spots, on silver discs, which were inserted in 
the tapes, about six inches from each extremity. The method 
adopted was as follows :—the tapes 4 and B were laid side by 
side in the troughs. These troughs were made of Kauri 
Pine (Dammara robusta), one inch thick, which being a 
light wood and a good non-conductor of heat was 
found well-suited for the purpose. Hach trough was about 
fifteen feet in length, so that they could be easily carried ; 
and whilst the measurement was being carried on with 
one hundred feet, the troughing for the next one 
hundred feet was being placed in position. There was some 
difficulty at the outset im devising suitable covers for the 
troughing—-so as to shade the tapes from the direct rays of the 
sun. A strip of blanket was used at first, but was not found to 
answer. After some trials, a board, sufficiently wide to shade 
the bottom of the trough, whilst allowing for ventilation, was 
used, with the best results. Our subsequent experience proved 
the boards to be reliable in every way. The troughs were 
supported upon pegs set on an even grade by means of a 
levelling instrument. Each sub-division of one hundred feet 
