74. The duties payable on the gross amount of the sale by auction shall be:One per cent on the first one hundred thousand dollars or fraction thereof, plus
One-half of one per cent on the next additional one hundred thousand dollars or fraction thereof, plus
One-third of one per cent on the next additional one hundred thousand dollars or fraction thereof, plus
One-fourth of one per cent on the next additional one hundred thousand dollars or fraction thereof, plus
One-fifth of one per cent on the next additional one hundred thousand dollars or fraction thereof, and so on, increasing the denominator of the fraction of the rate by one, for each next additional one hundred thousand dollars, or fraction thereof, in the gross amount of the sale.
For the purposes of this section, when an auction sale lasts more than one day, it shall be considered as one sale.