THE USE OF IRON. 75 



physical tests is rarely possessed by the designing and con- 

 structing engineer, even though it were possible for him to 

 give his personal attention to these details, hence, very prop- 

 erly, such work is now entrusted to an assistant making a 

 specialty of such work, or most usually to some reputable 

 inspection-bureau, the outgrowth of this condition. 



The necessity for, and extent of, this practice is clearly ex- 

 plained in a recent paper entitled "Shop and Mill Inspec- 

 tion," by Mr. W. O. Henderer, read before the Civil Engi- 

 neers' Club of Cleveland, and from which the following is 

 quoted : 



"There was a time when one man could comfortably 

 attend to such duties himself, and personally follow the prog- 

 ress of the material in all its various processes. The shops 

 and mills at which iron was manufactured, and where the fin- 

 ished parts of structures were produced, were often one and 

 the same; or, if not, the processes followed each other in such 

 rotation that one man could get from mill to shop and keep 

 proper consecutive track of the work. But the industry has 

 of late years grown to such enormous proportions and has ex- 

 tended over such a large area that it is impossible for one 

 man to properly inspect the work in all its stages. Bridge 

 companies now have a number of mills from which to order 

 the material necessary for their work. They are likely to 

 have plates from one mill, beams and channels from another, 

 and other shapes from still a third ; and the mills are often 

 great distances apart. Frequently, too, the shop is at work 

 on some portions of a contract while the mills are still fur- 

 nishing materials. It is manifestly out of the question for 

 any one man to thoroughly inspect work at all these places at 

 one time. He must have assistance in some way. 



" Men who have become expert and experienced in this 

 sort of work have made inspection their particular business, 

 performing this service at a compensation based on the ton- 



