The said board of trustees shall consist of the president and secretary of the board of directors of such public library, 2 employes contributing to said fund and 1 other member of said board of directors. The president and secretary of such board of directors shall be ex-officio members of such board of trustees. The 3 other members of such board of trustees shall be elected by ballot by the employes contributing to said fund at the time and for the terms, respectively, as follows: At the first election the contributors to said fund shall elect 1 of their number to serve for the term of 1 year and 1 of their number to serve for the term of 2 years and annually thereafter said contributors shall elect 1 of their number to hold office for the term of 2 years. At each election the contributors shall elect a member of the board of directors of such public library to serve as a member of such board of trustees for a term of 1 year.