DONATIONS ANNOUNCED. 127 
“Report of Progress,” 1882-83-84. Montreal,1885. ‘‘ Maps 
o accompany Report of Progress, 1882-83-84’; and ‘‘ Catalogue 
of Canadian Plants, Part II, Gamopetale,” by John Macoun, 
M.A., F.L.S. Montreal, 1884. From the Director, Geological 
and Natural History Survey of Canada. 
“The Australian Irrigationist,’’ No 13. Melbourne, 1885. From 
the Editor. 
The following papers were read :— 
“THe PapuaNs—ComMParaTIVE Nores oN Various AUTHORITIES 
WITH ORIGINAL OpseRvATIONS,” by William EK. Armit, F.L.S., 
F.R.G.S., Pages 95-116. 
A SHORT ACCOUNT OF THE MEASURE. 
MENT OF THE BASE LINE IN CON- 
NECTION WITH THE TRIGONOMET- 
RICAL SURVEY OF QUEENSLAND. 
BY 
W. A. TULLY, Hsgq., B.A., F.R.G.S., &c., Surveror GENERAL. 
(Pirate V.) 
I propose giving a short account of the measurement of the 
base-line in connection with the Trigonometrical Survey of the 
Colony, which was completed last year. 
A base-line is the foundation of a trigonometrical survey. 
On the accuracy of its measurement depends the correctness of 
the net-work of triangles, which are established by angular 
Measurements, commencing from the terminal points of the 
base. The exact measurement of a line on the earth’s surface 
is one of the most difficult operations that can be undertaken. 
Even with the greatest care and the most approved appliances 
only a close approximation to absolute accuracy can be relied 
on. Experience proves that no two measurements of the same 
