THE USE OF IROK. 55 



tance of using good grades of that metal, so that the decline 

 in safety, above suggested, has probably not begun. 



" Very naturally the reduced cost of steel, attended by a 

 growing confidence in its uniformity and high quality when 

 demanded, has led to a decided preference for that metal. 

 That this preference will not be modified under present con- 

 ditions seems very certain, but this fact will not, and very 

 properly should not, prevent the use of wrought iron of ap- 

 propriate grades when preferred. Since little assurance of 

 excellence is to be found in the mere names steel or wrought 

 iron, the really vital consideration is not so much which metal 

 as what grade of the chosen metal." 



Upon a subject where there is room for so wide an expres- 

 sion of individual opinion, and in view of the conservative ten- 

 dency which bids the manufacturer as well as the engineer 

 " Be not the first by whom the new is tried," there is little 

 wonder at the following expression from one of the most 

 long-established and eminently reliable and respectable metal 

 workers upon the use of steel or iron plate in stand-pipe con- 

 struction : 



*' We do consider iron plates more uniform in composition 

 and better adapted for stand-pipe construction, regardless of 

 question of cost, than steel plates of the standard chemical 

 and physical properties, as we are able to obtain those plates. 

 The difficulty the mills rolling plates meet with is that they 

 can not produce all plates of the quality they desire. 



"Our specifications for a stand-pipe iron plate are merely 

 that the plate shall be double refined and fibrous in nature, not 

 crystallized in its composition, 48,000 to 50,000 pounds ten- 

 sile strength, and made from such mixture of pig iron as we 

 know will unite in making a strong plate. We have used one 

 mixture of pig iron, comprising three different grades of pig, 

 for a period of twenty years in stand-pipe plates, and there 

 never has been a failure of one plate of this material. It 



