ยง 130. Contracts  with  corporations  for supply of gas. The municipal
  officers authorized by law to contract in behalf  of  any  city  of  the
  first  class, for the lighting of its streets may, from time to time, in
  the manner, upon the terms and with the conditions hereinafter  provided
  contract  in  behalf  of  such city with any corporation or corporations
  then supplying gas therein for a supply of gas to  such  city,  for  and
  during  such  specified  period  not exceeding fifteen years as shall by
  such municipal officers be deemed to be for the best interests  of  such
  city and of the inhabitants thereof.