PRELIMINARY EXAMINATIONS AND SURVEYS. 19 



may be made for the several parts of the work. However, it may be advisable to make 

 no further contracts after the delivery of the materials, but to build by hired labor. 

 This method is frequently adopted where funds are insufficient to enable an economical 

 contract to be arranged, but it has the objection that it requires the Government to 

 purchase or hire a plant, and it also requires, if it is to be economically carried out, an 

 engineer with a good practical knowledge of construction in all its details, such as the 

 use of engines, boilers, derricks, and appliances of all kinds; in fact, he should be not 

 only a good civil engineer, but also a practical master workman. 



The specifications for furnishing materials should describe the character and location 

 of the work and the facilities for transportation, and should state what the contract 

 is to include, the quality and quantity of materials required, fully classified and each 

 class described; the dimensions, the style of finish of each class, when and in what pro- 

 portions of each class delivery is to be made; the time the contract will expire, etc., etc. 



The specifications for building should state what the contract is to include, describe 

 the nature and depth of foundations, kind of coffer-dam required, amount and char- 

 acter of excavation and how classified, classification of masonry and method of ascer- 

 taining quantity, manner of placing cut stone, timber, concrete, filling, etc., quality 

 of cement, proportions of mortar and method of mixing, manner of fastening irons and 

 anchorages, etc., etc. 



Both drawings and specifications should indicate that the best class of material 

 and construction will be required, as long experience has shown that where a work of 

 improvement is intended to be permanent, as in slackwatering a river, the truest economy 

 lies in a construction that will require a minimum of repairs. 



