Examples from the Web for mainspring
He keeps time for a year or two, and then something happens to his mainspring and he gets the sack.The Best Short Stories of 1917|Various
You would fain be thought to take no share in government, while in reality you are the mainspring of the machine.Junius Unmasked|Joel Moody
This belief was the mainspring that kept the Southern Confederacy going, as it was also the corner-stone of its constitution.
It always remains the mainspring of intellectual life; when it ceases to be a motive power to thinking, thought is dead.Outlines of Educational Doctrine|John Frederick Herbart
Thenzipout went Mr. Toads tongue, like you uncoiled the mainspring of a watch, and the fly was gone!Left Half Harmon|Ralph Henry Barbour