From: Mark Glusker
Email: glusker@yahoo.com
If this is a really early Monroe, and the knob is fixed in place, I believe it is simply a means of rapidly moving the carriage from side to side. Lift up on the knob to raise the carriage, and then it slides freely back and forth. Much easier than repeatedly turning the T-bar at the front of the machine. If the knob comes out the end of the carriage and can rotate, this could be for clearing the numbers in the carriage. Later Monroes had a crank on the end of the carriage for this purpose - turn it one way to clear the revolution counter, and the other way to clear the results register. Can't really tell you for sure without a picture, but hopefully this can narrow it down a bit.
[arch3/_private/calc1_aftr.htm]