Both Uses of

function
in
Frankenstein - 1831 version

During the two years that had elapsed previous to their marriage my father had gradually relinquished all his public functions; and immediately after their union they sought the pleasant climate of Italy, and the change of scene and interest attendant on a tour through that land of wonders, as a restorative for her weakened frame.
p. 35.3

functions = responsibilities

It is your duty as a magistrate, and I believe and hope that your feelings as a man will not revolt from the execution of those functions on this occasion.
p. 203.3 *

functions = responsibilities (jobs)

Definitions:

(1) (function as in: Its main function is to...)
purpose, job, or natural activity
(2) (function as in: can't function well without sleep)
work or operate -- sometimes to work or operate normally or in a particular way
(3) (function as in: I'm attending a function tonight)
a social event or ceremony -- especially one attended for work or out of a sense of duty
(4) (function as in: oxygen is a function of altitude)
saying one results from another; or saying that the amount of one thing is dependent upon the value of another.

If x is a function of y, then x results from y; or the amount of x can be calculated based on the amount of y.
(5) (function as in: Amazon's new search function)
computer code that performs a specific task
(6) (function as in: a mathematical function)
a formula or mathematical expression that describes a relationship between variables
(7) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

For more specialized meanings in math and chemistry, see a comprehensive dictionary.