APPENDIX 255 



[NOTE. As to what constitutes a whole or completed work, see Chap. VI., 

 27. For the distinction bettveen a clause providing for the making good of 

 omissions, and an ordinary maintenance clause, see Chap. XVI., 10.] 



20. Extras Power to vary or omit work, etc. The contractor shall not 

 alter, in any way whatsoever, any of the work, except as directed in writing 

 by the engineer ; but the engineer shall have full power from time to 

 time during the execution of the contract to alter, amend, omit, or 

 otherwise vary any of the work, without in any way affecting or vitiating 

 the contract, and the contractor shall carry out such alterations, amend- 

 ments, omissions, variations, or directions, and be bound by the same 

 conditions, as far as applicable, as though the said alterations, amend- 

 ments, omissions, variations, or directions occurred in the contract. The 

 difference of cost, if any, occasioned by any such alterations, amend- 

 ments, omissions, variations, or directions, shall be added to or deducted 

 from the contract price as the case may require. The amount of such 

 difference, if any, shall be ascertained and determined in accordance with 

 the rates specified in the schedules of prices, so far as the same may be 

 applicable, and where the rates are not contained in the said schedules, or 

 are not applicable, they shall be settled by the engineer and contractor 

 jointly. But the purchasers shall not become liable for the payment of 

 any charge in respect of any such alterations, amendments, variations, 

 or directions unless the instruction for the performance of the same shall 

 have been given in writing by the engineer, nor unless such instruction 

 shall state that the matter thereof is to be the subject of an extra or 

 varied charge, nor unless the particulars of his claim shall be set forth in 

 writing by the contractor, and furnished to the purchasers within thirty 

 days after the execution of the same ; but subject to these conditions 

 being duly complied with, the purchasers shall be bound by such 

 particulars unless they or the engineer object thereto in writing within 

 thirty days after delivery thereof. 



In the event of the engineer requiring to dispense with or add to any 

 part of the plant or works to be done under this contract such reasonable 

 and proper notice shall be given to the contractors as will enable them to 

 make their arrangements accordingly. 



Unless the contractor shall otherwise agree in writing, the total sum 

 of money set out in the contract shall not be affected by such alterations, 

 amendments, omissions, variations, or directions to the extent of more 

 than 10 per cent, of the amount of the contract. Provided always that 

 in cases where goods or materials are already prepared, or any matter or 

 patterns made or work done that require to be altered in respect thereof, 

 a reasonable sum shall be allowed by the engineer. 



[For the meaning of " omission," see Chap. VI. , 34. For the limitation 

 of an engineer' s poivers under the extra clause, see Chap. XII., 8.] 



20A*. Extras to be authorised by writing. The contractor must not 

 execute any extra or omit any specified work whatsoever unless upon the 

 written order or authority of the engineer, or upon some plan or drawing 

 expressly given or signed by the engineer as an approved alteration. An 

 order form will be made out by the engineer stating the amount of the 

 extra or deduction agreed to in each case. The contractor must refer 



