Where the illegality of work done or of materials furnished under a contract is slight, or where judgment for the defendant will impose a severe forfeiture upon the plaintiff, courts are astute to discover ground for allowing the plaintiff to recover. "Where the plaintiff contracted to construct a building of combustible materials within fire limits of the city in violation of an ordinance, the plaintiff was denied recovery;95 but where a contract did not in its terms necessarily involve a violation of building laws, the fact that the plaintiff performed the contract with materials not allowed by law, was held not to preclude recovery.96

94 See infra, Sec. 1768.

95 Chimene v. Pennington, 34 Tex. Civ. App. 424, 79 S. W. 03.

96 Fox v. Rogers, 171 Mass. 546, 50 N. E. 1041 (commented on, supra, Sec.1761). So recovery for a heating plant was allowed, though the plans had been disapproved by an official inspector whose certificate was required by law and the plaintiff was aware of this. Ordway v. Newbury-port, 230 Mass. 306,119 N. E. 863. In Konig v. Mayor, etc., of Baltimore, 128 Md. 465, 466, 97 Atl. 837, the court said: "Where a contract for the construction of a public filtration plant is entered into by a contractor and a municipality, honestly on both* sides, and with no intention of violating the law, and yet the contract is in conflict with the city's charter powers, then, after the work is done, courts should not be zealous in depriving the contractor of his pay or profits, when it is not shown or claimed that it was otherwise than well done, but shown to be of great benefit to the public, and when the taxpayer who brings the suit shows no injury to himself or to the city, and who after merely instituting such a suit used no diligence in bringing it to a conclusion. While ignorance of the law is not a valid excuse, contractors engaged in work all over the country cannot be supposed to keep familiar with every detail of municipal charters." In Josephs v. Briant, 108 Ark. 171, 157 S. W. 136, a contract by which plaintiff was required to procure certain letters and return them to the writer was held not illegal, though it was agreed that they should be transmitted through the mails and they were not mailable under thef ederal statutes. The court considered the method of return merely an incidental matter.