The sheriffs of the several counties in this State shall procure for their respective counties a sufficient number of voting compartments, shelves and tables for the use of electors, which shall be so arranged that it shall be impossible for one voter at one table, shelf or compartment to see another voter who is preparing his ballot. The number of such voting shelves, tables or compartments, shall not be less than one for every one hundred electors at each voting precinct. Each shelf, table and compartment, shall be kept furnished with a card of instruction posted in each compartment, and proper supplies and conveniences for marking the ballots by electors.