The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium Before the Common Era.
 
Can you tell how many lentilles wide the sluice is? A picture proof would be good here, just to know how you counted it.
Don't forget to use the tools given by the Pink Chest Keepers.

Send the number to the Pink Chest Keepers, write it down as a backup in your book and turn to the next page.