How To Call Health Script From Another Script ?

hello i have An Empty gameobject i added health bar script to it as u can see in the picture it is called ( HealthBar )

 #pragma strict
 public var health : float; // var helath
 var texture1: Texture2D; // texture 2d
 var mat : Material; // material
 var x : float = 0;
 var y : float = 0;
 var w : float;
 var h : float;
 function Start () {
 health = 1000; // begining health is 100
 }
 function OnGUI(){
 if(Event.current.type.Equals(EventType.Repaint)){ //Is the game being drawn?
 var box : Rect = new Rect(x, y, w, h); // the postion of the drawn on screen
 Graphics.DrawTexture(box, texture1, mat);  // you draw the bo and texture2d and material
 }
 }
 function Update () {
 var healthy : float = 1-(health/100);
 if(healthy == 0){
  
  
  
 healthy =.1;
 }
 mat.SetFloat("_Cutoff", healthy);
  
 if ( health <= 0 )
 {
  
 GameOver() ;
 }
  
  
 }
  
  
  
 function GameOver ()
 {
  
  
 Application.LoadLevel("GameOver") ;
 }
 function AddHealth ()
 {
 health +=30 ;
 }

and that is the code of HealthBar Script this Script Called ( HelathBar1) what i want is to make the health Float Increase By ( 30) if a cube hit a bullet

the problem that when the bullet hit the cube nothing happen first i want to ask ? where should be the script who call the health bar script on ? on bullet or on the cube ? secound how to call the health bar and increase the health of it by ( 30 ) and that is my trying but it is not working

 #pragma strict
 private var player : GameObject  ;
  
 private var   HealthScript  :  HealthBar1 ;
  
  
 function Start () {
 //var  HealthScObject = GameObject.FindGameObjectWithTag ("Player");
 //if (HealthScObject != null)
 //        {
 //            HealthScript  =  HealthScObject.GetComponent ("HelthBar1");
 //        }
 //        if (HealthScript == null)
 //        {
 //            Debug.Log ("Cannot find 'GameController' script");
 //        }
  
  
 }
  
  
 function OnTriggerEnter (other : Collider)
 {
 if ( other.gameObject.tag == "Player")
 {
  
 other.GetComponent(HealthBar1).health += 30 ;
  
  
  
 }
  
  
 }
  

it is increase the health by ( 30 ) when it is Hit the HealthBar Empty Object who have the script (HealthBar1 )

if added Health bar script to the bullet it is working also so what should i do to call it with out added it to the bullet hope you help me