THE PAYMENTS 85 



EXECUTION OF THE CONTRACT 



The bidder to whom the contract is awarded is required 

 to execute the agreement within a specified time. To do 

 this he must affix his signature to the contract form in which 

 all of the prices have been entered by the clerk of the board. 

 The agreement is secured by individual bonds or a surety 

 company bond, which constitutes a part of the contract. 

 As mentioned before, a surety company usually requires 

 a contractor to take out liability insurance before it exe- 

 cutes the contract bond. After the contract is signed and 

 the bond duly executed all of the proposals together with 

 the accompanying bonds become at once void. 



STARTING THE WORK 



Active operations must be begun within a specified 

 number of days, which is frequently ten. 



THE PAYMENTS 



Monthly Estimates. At the end of each month it is 

 customary in many contracts to make a payment, but not 

 in the whole amount of the work done. Sometimes 10 

 per cent is retained and sometimes 25. It is not nec- 

 essary for the engineer to make an accurate determination 

 of the quantities, although, if to be on the safe side he 

 underestimates the work, the contractor may be dissat- 

 isfied, especially if his payroll and other obligations are 

 heavy. 



The Final Estimate. When the work is satisfactorily 

 completed a final estimate is prepared which is as exact as 

 it is possible for the engineer to make. The final payment 

 is equal to the total value of the work less the sum of the 

 previous payments. 



