Making a simple ticking clock in AS3 with .as files

I'm making a simple clock in AS3 as seen on youtube (Doug Winnie) but I want to put the code into separate .as files. This is what I have so far but I keep getting the error 1046: Type was not found or was not a compile time constant: secondHand. But it's saying that the location of the error is Line 3 of Clock, but secondHand isn't even mentioned here?

package  {

import flash.display.MovieClip;

public class Clock extends MovieClip {

import flash.events.TimerEvent;

import flash.utils.Timer;

import flash.events.MouseEvent;

var clockTimer:Timer = new Timer(1000, 60);

    public function Clock(e:TimerEvent):void

    {

        clockTimer.addEventListener(TimerEvent.TIMER_COMPLETE, endTimer);

        }

        function endTimer(e: TimerEvent): void

        {

        trace("Finished");

        }

    }

    }

// startButton and stopBtn are instances of GameButton.

package  {

import flash.display.MovieClip;

import flash.events.MouseEvent;

public class GameButton extends MovieClip {

    public var startButton : GameButton;

    public var stopBtn : GameButton;

    public function GameButton():void

    {

    createListener();

    startButton.buttonLabel.text = "Start";

    stopBtn.buttonLabel.text = "Stop";

    }

    public function createListener():void{

        startButton.addEventListener(MouseEvent.CLICK, startTimer);

        stopBtn.addEventListener(MouseEvent.CLICK, stopTimer);

    }

    function startTimer(e:MouseEvent):void

        {

            clockTimer.start();

            trace ("Timer started.");

            startButton.visible = false;

        }

        function stopTimer(e:MouseEvent):void

        {

            clockTimer.stop();

            trace("Timer stopped.");

            startButton.visible = true;

        }

    }

}

//

package  {

import flash.display.MovieClip;

import flash.events.TimerEvent;

public class secondHand extends MovieClip {

    public function secondHand(e: TimerEvent):void {

        // constructor code

        clockTimer.addEventListener(TimerEvent.TIMER, moveHand);

    }

    public function moveHand(e:TimerEvent):String

    {

        secondHand.rotation = secondHand.rotation + 6;

        trace("timer");

        }

    }

}