Intersting possible derivation of "By jiminy" above.

"Chambers Twentieth Century Dictionary" gives :
"jiminy, See geminate;

geminate v.t.to double.-adj.(bot.) in pairs .............Gemini the twins, a constellation...... geminy (Shak.), a pair, esp of eyes.-interj. expressing surprise- also spelt gemini, gemony, jiminy. [L. geminus, twin]

Nigel