(a) The depository shall pay out no money save upon the order of the board of commissioners and upon a warrant signed by the person designated by the commissioners.
(b) Every warrant shall state upon its face to whom, the amount, and the purpose for which it is issued.
(c) All warrants shall be dated and shall be numbered consecutively, in a record to be kept by the board of the number and amount of each. No warrant shall be paid unless there are in the treasury funds enough to pay all outstanding warrants bearing a lower number.
(d) No warrants shall be increased by reason of any depreciation in the market value thereof, nor shall any contract or warrant be made payable or paid in anything but currency.