354 
THE WELDON RANGE-FINDER. 
his tape, which the latter holds close to his glass. The auxiliary base- 
finder man sees the distant object direct through the open shutter of 
the angle-finder man's glass, (while he holds the tape in the same hand 
as he holds his own.) He moves backwards or forwards until he sees 
the distant object direct through the angle-finder's shutter, and the 
reflection of the base-finder man's glass in one line, and he follows the 
movements of the two other men for this purpose. On the angle-finder 
saying “ correct" he reads off the range marked on the tape. 
I record work with the three glasses as follows - 
October , 1880. Man on horseback , walking. 
Object: Helmet. Fair light. 
Name. 
Position. 
Time. 
Results 
obtained by. 
Range. 
Com¬ 
menced. 
Ended. 
Total. 
Br. K . 
/F. 
1 
I 
Aux. Base. 
810 
Br. W. ... 
B. F. 
j>6.15 
6.16 
1 
Pacing. 
800 
Br. H. 
A.B.F. 
1 
Measured. 
826 
Same man halted on signal, but moved some 3 lengths. 
Range for accuracy 
795 
In these lessons, each man has a pole, and plants it when correct," 
to enable measurement to be tested. 
If anybody using the glasses will take pains to record the result of 
his work just as he finds it, without attempting to correct errors (which 
at first occur very frequently), he will soon notice a great improvement 
in his work. 
Three men work the range-finder when out with the battery, but 
so far the auxiliary base-finder has not been very satisfactory, for the 
man who uses the auxiliary base glass generally finds his horse a 
nuisance to him, and he also frequently finds the angle-finder's horse 
in his line of sight, but I hope to get over this as we gain experience. 
Two men work very quickly, but sometimes their horses check them in 
pacing the base, and it is perhaps nearly as quick to make the third 
man a horse holder. I have tried different plans. First of all the 
three men galloped out, numbered 1, 2, 3. 1 = angle-finder, 2 base- 
finder, 3 horse holder. 1 and 2 dismount, give their horses to 3, and 
take the range in the usual way, either pacing or measuring the 
base. This, if the base is at all a long one, takes some two minutes 
generally. 
Then I tried two men alone. They gallop out; have the object 
pointed out; agree on the exact spot of the object they mean to take. 
Ho. 1 dismounts, 2 turns his horse to the left, looks through his, 
