AMERICAN INSTITUTE. 59"/ 



frames in which the glass was pasted to the engraving, they will 

 always at certain times present a moist film. 



Dr. Reid of England, the ventilator of the new houses of Par- 

 liament, next spoke — Some stones are undoubtedly so porous that 

 they will serve as filters. Glazed bricks are extremely valuable 

 for the opposite reason." Draining tiles often crumble because of 

 their porosity. A porous wall is therefore a bad wall. As to 

 foundations, it is necessary that walls standing in damp places 

 should be well protected from springs and other places of mois- 

 ture. In this way concrete often ceases to be concrete. As to 

 the silicate of lime, ten or twelve years ago many interesting 

 experiments were made. A patent had been taken out for the 

 formation of a sort of hard glass — a silicate such as exists in 

 nature. Capt. Smith had pointed out a remarkable fact — the 

 conclusion being that pure oxide of iron, free from acid, will pull 

 down lime from its solutions in water. No doubt the hardness 

 of the old Roman cements arose from the gradual formation of 

 a true silicate of lime in the compound, and the hardness of 

 mortar generally may be in ratio to the formation of this peculiar 

 body. Dr. Reid spoke very approvingly of double windows. 

 Some persons thought it advisable to place the panes as far apart 

 as possible. 



The Chairman called up the subject for the next meeting. 



Mr. Tillman requested that the subject selected by the com. 

 mittee, viz : The extent and mode of using iron in building, in 

 place of other materials. The question was unanimously adopted. 



The Club adjourned. 



H. MEIGS, Secretary. 



April 9t/i, 1856. 



Present— Messrs. President Pell, Backus, Leonard, Chambers, 

 Dr. Smith, Slater, Lindsay, Cowdin, Fisher, Godwin, Creamer, 

 Tillman, Thompson, and others, 33 members in all. 



Samuel D. Backus in the chair; Henry Meigs, Secretary. 



The minutes of the last meeting were read in part; on motion 

 the reading of the residue was dispensed with, and the minutes 

 approved. 



On motion, Mr. Lindsay was requested to exhibit his model 

 machine for grinding and polishing glass plates, kc. The trans- 

 lucent and the opaque plates exhibited had very perfect polish 

 and true surfaces. He described the whole modus operandi at 



