CHAPTER XL 

 PAINTING. 



Discussion. A lay-writer has clearly defined the science 

 of engineering as <( Common sense, directed by theory and 

 practice, to works of construction," and he might have added 

 11 whose comparative permanency was a prime consideration." 



This last, as a desideratum, it seems is frequently omitted 

 by the engineer as well, and content with selecting materials 

 and designing members, scant consideration is given to the 

 necessity for effectually preserving the works of his creation 

 when once they have been completed and tested. 



Engineers' specifications for the protective coating for 

 iron or steel too often exhibit a variability which permits al- 

 most anything in the nature of paint to be applied as a pre- 

 servative, provided it is not too expensive, dries quickly, 

 covers the ordinary stains, and for a time looks well. 



A more satisfactory explanation is to attribute this neglect 

 to a lack of knowledge rather than to a lack of interest, which 

 is more to be condoned in view of the absolute diversity of 

 opinion of those recognized as authorities as to what consti- 

 tutes the best method of protecting metallic structures from 

 corrosion and decay, and the further fact that possibly in the 

 practice of the individual he has developed the anomalous 

 idea that the cheapest paints have at times evinced, in actual 

 use, superior qualities to scientifically correct and high-priced 

 compounds. 



A communication was received a short time since from a 



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