The opinion of the court was delivered by

This writ brings up a conviction for violation of a city ordinance with reference to the heating of buildings rented for residential or business purposes where people are employed. The essential provision is that which requires that every occupied room shall be heated “so- that a minimum temperature of sixty-eight degrees Fahrenheit may be maintained therein at all such times.” The words “at all such times” are defined by the- ordinance “to include the time between the hours of six a. m. and ten p. M. in- a building or portion thereof occupied as a home or place of residence and during the usual working hours established and maintained in a building or portion thereof occupied as a business establishment, of each day, whenever the outer or street temperature *35shall fall below fifty degrees Fahrenheit.” The proof fails to show that there was a failure to provide for the minimum temperature required at any time when the outer or street temperature fell below fifty degrees. ■ There was proof that at the time the examination was made on, behalf of the city the rooms were heated to a temperature less than sixty-eight degrees,, but there was no, proof that at that time the outer or street temperature was below fifty degrees. Necessarily, the proof is required to be strict in penal cases of this character, and for this failure of proof the conviction must be set aside. .It will be time enough to pass upon the reasonableness of the ordinance when that question is necessarily before us.