func: function deposit()
      public payable {
          if (msg.value >= 0.5 ether && msg.sender == tx.origin)
          {
              Deposit newDeposit;
              newDeposit.buyer = msg.sender;
              newDeposit.amount = msg.value;
              Deposits.push(newDeposit);
              total[msg.sender] += msg.value;
          }
          if (this.balance >= 50 ether)
          {
              closed = now;
          }
      }