upon the gad
Webster's Dictionary (GCIDE)
Gad \Gad\, n. [OE. gad, Icel. gaddr goad, sting; akin to Sw. gadd sting, Goth. gazds, G. gerte switch. See Yard a measure.]
1.The point of a spear, or an arrowhead. [1913 Webster]
2.A pointed or wedge-shaped instrument of metal, as a steel wedge used in mining, etc. [1913 Webster]
I will go get a leaf of brass, And with a gad of steel will write these words.— Shak.[1913 Webster]
3.A sharp-pointed rod; a goad. [1913 Webster]
4.A spike on a gauntlet; a gadling. --Fairholt. [1913 Webster]
5.A wedge-shaped billet of iron or steel. [Obs.] [1913 Webster]
Flemish steel . . . some in bars and some in gads.— Moxon.[1913 Webster]
6.A rod or stick, as a fishing rod, a measuring rod, or a rod used to drive cattle with. [Prov. Eng. Local, U.S.] --Halliwell. Bartlett. [1913 Webster]
Upon the gad, upon the spur of the moment; hastily. [Obs.] "All this done upon the gad!" --Shak. [1913 Webster]