A System of Accurate Measurement by means of 
long Steel Ribands. 
By G. H. Kyrsss, L.8. 
[Read before the Royal Society of N.S.W., 3 June, 1885.] 
WHueEN measuring in precipitous, or even undulating country, great 
difficulty has hitherto been experienced by surveyors, in obtaining, 
with any degree i accuracy, the horizontal values of the distances 
between any g given points 
In the wHarrayar Pocket-book, ” published by the yooh ot 
General of the Colony, Mr. Surveyor Sheaffe, in an article 
‘*‘ Hypotenusal Measurement,” bearing the date August, 1878, 
Seeger eae the use of long steel ribands in rugged. country in 
u of the one-chain tapes, then generally used. The results by 
fis ts ethod suggested were incomparably better than those given 
by previous methods, 
em of measurement, when properly developed, is 
capable of yielding ‘inches scarcely inferior to the most careful 
trigonometrical surveys, and with comparatively little expenditure 
of time. The precision attained by its means in all classes of 
country is such as surpas the most sanguine expectations of 
surveyors eight or ten years ago. 
The novelty of the method is attested by the fact of its recent 
origination in this Colony, the credit of which belongs, I believe, 
to Mr. Sheaffe, of its still more recent theoretical development 
and subsequent practical testing by the writer, and by its absence 
from the standard works on surveying. 
The accurate system of hypotenusal measurement may thus be 
briefly described :— 
The distance between two given points is indicated upon a steel 
riband stretched between them, at a tension such that the result 
given is, in all cases, the same as that given when the riband is 
resting throughout its length, upon a smooth plane surface at a 
tension which makes it equal to an absolute standard at some 
given temperature. To this indicated distance corrections are 
applied for the variation from standard temperature and inclina- 
tion with the horizon. 
In practice, when the country to be surveyed approximates toa 
plane surface, the riband may lie wholly upon it ; the angle of its 
inclination with the horizon being ascertai ned. by observing a a 
