No. 216.] 219 



either is employed alone, the peices of metal are so nearly homoge- 

 neous, that the contraction or expansion will be alike in proportion 

 to size, all through any number of pieces in any given structure, and 

 will not in the least endanger the general permanence. 



The third objection applies to the cost, and is perhaps the only 

 point that has any real claim to consideration. 



The annual and perhaps wasteful destruction of timber, probably 

 points to the fact, that this material will soon be so much less in 

 supply, that the price will be raised in proportion; while the im- 

 provements in the manufacturing the exhaustless iron supplies of the 

 country, are more likely to lower the cost of the material, than to 

 raise it. 



With this double contingency in view, any information that will 

 spread the knowledge of the fact, that iron, which is indestructible 

 by fire, that protects itself from lightning, is impervious to weather, 

 and to vermin, permanent in place, but easily removable, and recon- 

 structable without injury, may be looked forward to, as ready to 

 furnish many more peaceful blessings to the human race, than it now 

 does, and on terms that will make it available for these uses, where 

 cost and permanence are duly weighed against cost and destructi- 

 bility of timber. 



Those who have not considered this subject may treat these sug- 

 gestions with levity, or indifference, perhaps with ridicule and de- 

 rision. 



But the undersigned was among the earliest advocates of ocean 

 steam navigation, and iron ships, and the derision and ridicule he 

 then encountered, has fully recoiled on those with whom it origi- 

 nated. He therefore " abides his time," and remains. 



Dear sir. 



Yours very truly, 



WM. SERRELL. 



Civil and Mechanical Engineer, 

 JVo. 201 Broadway, JVew-York City. 

 To T. B, Wakeman, Esq , j3w». Institvte. 



