What will be the reading on a spring balance if both ends applied 1 N ?

Imagine a spring balance hanging from the ceiling with a 1 N weight attached to its bottom.

Assume the balance has negligible mass.

the force applied to the bottom end is, 1 N.

The force applied to the top end is, 1 N.

The balance reads, 1 N.



The most satisfying explanation I can think of is also the simplest:
A spring balance is the instrument designed to measure tension.
(or compression, if it's being compressed)

In a rope, tension is the force that a part of the rope is exerting on its neighboring parts.
For a massless rope held straight by forces of magnitude F at the ends, the tension in any part of the rope is simply the F
Meaning, if you look at the left and right halves of the rope, each half pulls the other by a force F at the place they meet.

If a spring balance held by 1 N forces at both ends read 2 N, then that spring would be bad for measuring weight (the thing spring balances are most often used for) because each time you'd have to divide the quantity by 2. 

pls post a sketch showing the arrangement of such balance and the applied forces