The first reference to "side slip" I was able to find dates back to 25th June 1910. Sorry, no forward slips, even the Yankee book of aerodynamics par excellence only talks of side slips (Aerodynamics for Naval Aviators). The good book also says about crosswind take off and landing, "Since the airplane must make a true path down the runway, a crosswind during take off or landing will require that the airplane be controlled in a side slip. The rudder must have sufficient control power to create the required sideslip for the expected crosswind".
http://www.flightglobal.com/pdfarchive/view/1910/1910%20-%200495.html