Rashi mentions what the spies carried on their shoulders: “Eight of them took a grape cluster, one took a fig, and one took a pomegranate. Yehoshua and Calev did not take anything, for the intention of the others was to present a slanderous report, saying, ‘Just as its fruit is extraordinary, so its people are extraordinary.’ If you wish to know how much one of them carried, learn from the stones they set up at Gilgal: Each man carried on his shoulder one stone from the Yarden and set it up at Gilgal. The Sages weighed them, and each stone weighed forty seah. It is a fact that the load a person can carry on his shoulders is only a third of the weight of the load he can carry when others help him lift it.” (Sotah 34a)