PHP Notice: Trying to get property 'amount' of non-object in Psy Shell code on line 1

Hi guys I have a model employee and transaction. ( Employee hasMany Transaction while Transaction belogsTo Employee

namespace App;

use Illuminate\Database\Eloquent\Model;

class Employee extends Model
{
    //
    //create a relationship between employee and transactions
    public function transactions()
    {
    	return $this->hasMany('App\Transaction');
    }

}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Transaction extends Model
{
    //
    //create a back relationship with Employee model
    public function employee()
    {
    	return $this->belongsTo('App\Employee');
    }
}

The problem is when accessing the reverse relationship with tinker

Transaction::find(1)->employees->amount; PHP Notice: Trying to get property 'amount' of non-object in Psy Shell code on line 1 => null

Any experience please