Wiring of simple wall switch
The outlet is not "further down". Electrical power is delivered to the outlet first, and the switch is "further down": 



Constant-hot power is delivered from the outlet box to the switch, and switched-hot is returned to the outlet via the same cable.

(The NEC specifies that when a cable does not contain a neutral wire, the white wire can be re-marked for another use, and when a constant-hot is in the cable, it must be assigned to the white wire. This leaves the black wire to be re-marked as the switched-hot.) 

Following Harper's recommendation, I have illustrated black tape for the constant-hot and red for the switched-hot. 

(Switch loops are no longer wired like this, as the widespread use of smart switches has changed the standard so that a neutral connection is now required in every switch box.)