46 
THE WELDON EANGE-EINDEE. 
moving, makes an angle with him and the object; and when that is 
effected he stands steady. No. 2 now sees in the angle-glass whether 
the reflected object falls to the right or left of No. 1. If on the right; 
No. 2 must retire; to increase his distance from No. 1; if on the left;, 
he must advance; to lessen his distance. After each move No. 2 halts 
and stands steady; for No. 1 to make a fresh angle. 
“In this manner Nos. 1 and 2 alternately move and halt until they 
get the object fairly reflected on each other. 
“ The distance between them is then measured; to determine the 
range of the object.” 
In practice Major Weldon either paces the base (which from 
practice he does very correctly; and obtains very fairly accurate 
results); or he measures it by a line of thin cobbler's twine—a material 
he finds to answer better than tapes, &c. Of this line he carries 
150 yds. (answering to a 3000 yds. range), wound on a simply con¬ 
structed reel, marked and numbered at every five yards. Each of 
these marks correspond to 100 yds. of range, and are so figured. No 
strain comes on this line. The man measuring moves straight from 
point to point; the line, as it unwinds from the reel, lies fair on the 
ground. 
In rewinding the man walks rapidly back, winding up as he goes 
instead of pulling the line to him. The wooden disc or reel for 
150 yds. of this measuring twine is so thin that it can be used in the 
highest wind. 
The ease with which the range of moving objects is obtained by 
two observers with the Weldon instruments is very remarkable; but 
for such objects practiced men are required. The distance of infantry 
firing from under cover has been ascertained by the puff of smoke from 
their rifles. The position of hidden guns could doubtless be obtained 
in the same manner. 
St. Thos.’ Mount, Madras, 
August 20, 1879. 
