At regular meetings for the transaction of business, the board of supervisors may sit for a period not longer than ten days in any one month. At meetings for the transaction of business under the revenue laws, the board may continue in session as long as business may require. However, in counties having a population of more than forty thousand, and in counties having two court districts, the board may continue in session at any other regular meeting than revenue meetings for a period not longer than twelve days in any one month. Furthermore, the board of supervisors may recess from time to time, subject to the limitation herein provided, to convene on a day fixed by an order of the board entered on its minutes, and may transact any business coming before it for consideration.