AMERICAN INSTITUTE. 605 



Many of the columns may be removed without injury to the remainder 

 of the structure, which, if several stories in height, will stand firmly upon 

 the four corner columns, or other equivalent in relative position. 



"To sum up the advantages of iron buildings, which have been rather 

 alluded to than urged upon your attention, I would direct you to consider: 



"1. The great, facility with which any arehitecti>ral design may be car- 

 ried out in iron. 



"2. The great economy of space that may, if necessary, be obtained — 

 inasmuch as a much thinner wall of iron may be made stronger than any 

 stone wall now constructed. I do not mean to enter into any consideration 

 of figures, for the reason that you are all familiar with them, and I hold 

 a suggestion, which you can each elaborate, contains more force than any 

 array of numbers — but it may not readily occur to you that a cast-iron 

 column, made of iron of only ordinary hardness, would rise to the height 

 of several miles, before its own weight would crush it. And this leads me 

 to another point which I wish to impress upon you, namely, that with such 

 enormous strength, there need only be employed skill and knowledge in the 

 construction, to render an ordinary iron building, beyond all comparison, 

 the strongest that can be made. 



"3. Economy in the construction of foundations, usually so expensive a 

 part of the builder's work ; and the safety of the building, notwithstand- 

 ing the foundation may be imperfect. I would not have you imagine that 

 I would either advocate or countenance carelessness ; but every man is 

 aware how many unlocked for casualties happen to a foundation, often dis- 

 astrous in their results to the superstructure. The advantage gained by 

 the use of iron for the building in this regard lies herein, that if part of the 

 foundation, notwithstanding all care used, shall give way, the superstructure 

 will be still unharmed. 



" 4. A not unimportant consideration for New Yorkers is, if at any time 

 the owner wish to move his building, he may do so, being only at the 

 expense of the actual removal, and having his entire house in as good con- 

 dition as when first made, losing nothing of the material. 



" 5. Security against lightning. The electricity being diffused over a 

 large surface, thus loses all its intensity. 



"6. Facility of ventilation. 



"7. The impervious nature of the material preventing dampness and 

 mildew, and consequently decay. 



" 8. Its durability, outlasting all the stone that ever was quarried, 



" Lastly. Its incombustibility. All public buildings, and siich private 

 buildings as are used for the storage of valuable goods, or works of art, 

 should have the interior at least constructed with a view to the prevention 

 of fires. Without the aid of iron this is impossible." 



Mr, Johnson inquired as to the effect of expansion and contraction of 

 the iron ? 



Mr. Ayrcs replied that in all Mr. Bogardus' experience with iron build- 

 ings, it was found to be practically unimportant. 



