SCOUTING FOR GIRLS 
471 
Diagram D. To Test a Right Angle 
A right angle can be tested by measuring off 3 feet on 
one side of the corner and 4 feet on the other side, as 
shown in diagram d. If the distance between the two 
points is 5 feet the angle is true; if not 5 feet move one 
point as much as is necessary to make 5 feet. 
South American natives estimate height fairly correct- 
ly by turning the back to the object, walking straight 
away from it to the point where the top of the object 
can be seen by bending over and looking between the 
legs. Plant a peg at this point and the distance from the 
peg to the base of the object is roughly equal to the 
height. . 
Sound travels at the rate of 365 yards every second, 
as many yards as there are days in the year. By count- 
ing the seconds between seeing the flash from a gun, 
or the steam puff from a locomotive and hearing the 
sound of the explosion or whistle it is possible to figure 
the length of the distance between yourself and the gun 
or locomotive. 
It is said that the number of seconds between a flash of 
lightning and the thunder will give the distance between 
you and the place where the lightning struck. 
We use weighing machines or scales in buying food, so 
that we may compare the actual amount of food we buy 
with a standard weight, otherwise there would be much 
confusion and business could not be carried on between 
peoples. For this reason we use pint, quart, peck and 
