Lord Wrenbury :-

The appellant is a building contractor. The respondents are restaurant keepers, who may be called the building owners. The question on the appeal is as to the construction of a contract between these parties for works of alteration, construction and fitting up in a restaurant and public dining room on the first floor over 119½, King Street East, in the City of Hamilton. The contract is dated 5th March, 1919, and is made between the building owners of the first part and the contractor of the second part. The relevant clauses are three in number, and for convenience will be referred to as the first, second and third clauses.

After a recital that the contractor has agreed to supply certain materials and perform certain services, the deed proceeds by the first clause as follows :

"Now this agreement witnesseth that in consideration of the sum of $ 3,000, to be paid as follows : $ 1,000 on the signing of this agreement further sum of $ 1,000 when it appears to the satisfaction of all the parties hereto that materials have been furnished and services performed to the extent of $. 2,500, and the balance or sum of $ 1,000, thirty days after the completion of this agreement,