140 THE LAW AFFECTING ENGINEEES 



common- sense principle that where performance of a condition 

 is rendered impossible by one party to a contract, the other 

 party is exonerated from the performance of it. At the same 

 time the contractor who undertakes to do the work within a 

 specified time must needs perform his contract, or else he may 

 lose the whole benefit accruing from the contract (Munro v. 

 Butt, 1858, 8 E. & B. 738). Interference by the employer 

 may also cause delay and render it equitable for the Court to 

 allow an extension of time. As to this see Chap. XV., 8, 

 post. 



6. Extension of time by engineer. By far the most 

 satisfactory way of dealing with the question of time, is to 

 allow the engineer to grant such extension as he may con- 

 sider reasonable. It is easy to do this by apt words in the 

 contract. Numerous causes for unavoidable delay occur after 

 the work has commenced. If the contractor applies to the 

 engineer for his decision as to an extension of time, he is 

 bound by that decision. In Sattin v. Poole, 1901, 2 H. B. d 

 337, the plaintiff agreed to build a house for the defendant. 

 The work was to be completed by a certain day, but the con- 

 tract provided that if in the opinion of the architect, the work 

 was delayed by reason of authorised extras or additions, or in 

 consequence of the contractor not having received in due time 

 necessary instructions from the architect, for which he should 

 have applied in writing, the architect should make a fair and 

 reasonable extension of time. The work having been delayed, 

 the builder applied for an extension, but the architect did not 

 reply at once. The builder then sued for 681 which had 

 been allowed on a certificate, subject to the question of penal- 

 ties for delay. After this the architect wrote granting an 

 extension, but not to the actual date of completion. The 

 builder then sought to call evidence to show that the delay was 

 caused by the architect in ordering extras. In effect, he wished 

 the Court to go behind the decision of the architect. This the 

 Court declined to do, holding that the architect's ruling was 

 final. "The construction of the clause," said the judge, "is 

 that the parties did not intend to let it be held that there was 

 any delay, unless the builder applied to the architect." 



The fact that the engineer has issued his final certificate 

 may, as will be seen hereafter, amount to an implied extension 

 of time (see Chap. XV., 13, post, and case there cited). 



