Unity scripts fail

using UnityEngine;
using System.Collections;

public class ScrollObject:MonoBehavior {
    public float speed = 1.0f;
    public float startPosition;
    public float endPosition;

    void Update() {
        // Move each frame x position little by little
        transform.Translate (-1*speed*Time.deltaTime, 0, 0);
        // Check if the scroll has reached the target point
        if(transform.position.x<=endPosition)ScrollEnd();
    }

    void ScrollEnd() {
        // Return the scrolling distance
        transform.Translate(-1*(endPosition-startPotion), 0, 0);
        // Send messages to components attached to each game object
        SendMessage("onScrollEnd", SendMessageOptions.DontRequireReceiver);
    }
}

Asset/Script/ScrollObject.cs(21,56): error CS0103: The name `startPotion' does not exist in the current context
Assets/Script/ScrollObject.cs(21,27): error CS1502: The best overloaded method match for `UnityEngine.Transform.Translate(float, float, float)' has some invalid arguments
Assets/Script/ScrollObject.cs(21,27): error CS1503: Argument `#1' cannot convert `object' expression to type `float'