Polytechnic Association. 789 



weather forever, and make a very durable and substantial surface, at 

 but little more than the expense of brick. But, after all, this was only 

 a scheme ; for the iron-clad houses ceased to be built, for the reason 

 that brown stone fell to two-thirds its former price, and that killed 

 the iron-clad houses. 



Mr. J. K. Fisher — I think it is a pity that the iron-clads did not 

 also kill the brown stone house; for it is the ugliest color that is used 

 in building. 



The President — There is such a difference between the expansion 

 of iron and any sort of enamel, that enameled iron cannot be expected 

 to be very lasting. 



Dr. L. Bradley — I recollect that when that very objection was 

 made by Dr. Kich, it was answered by the fact that the specimen had 

 already suffered all the ghanges of heat from some 200 deg. F. down 

 to zero, and still remained perfect. 



Mr. Partridge stated that samples of similar work done by pro- 

 tecting plates in Belgium, bore no comparison, in the perfection of 

 the coating, or in the regularity of the design, with work done from 

 the protecting plates made by the American machine in Newark, 

 specimens of which he exhibited. 



Fike Escape. 



Mr. Sharp exhibited a new fire escape, consisting of a brass cylinder 

 with a spiral groove around it, the friction of which, upon a rope 

 passing through it. is sufficient to enable a man to descend from the 

 window of an upper story with safety. One end of the rope is 

 fastened to a bedstead or other fixed object near the window, and the 

 person sits in a seat formed of leather straps attached to the brass 

 cylinder. If the descent is too rapid, a slight pull upon the rope 

 below the apparatus will increase the friction to any desired extent. 

 The whole apparatus, including the rope, may be packed in a small 

 box, and weighs but about three pounds, costing about ten dollars. 



The President — Would it not be cheaper if made of iron ? 



Mr. Sharp — Brass is cheaper in this case than iron, because this 

 screw can be finished more easily in brass. In case of a fire, if this 

 apparatus was at hand, a man could remain in a building in flames, 

 saving the property, until the very last minute, and then come down 

 with safety. Even if the flames should reach the rope, he would 

 reach the ground before it would burn. 



The President — It would be very easy to make the rope fire proof. 

 The proper way would be to make the fiber fireproof, before made up 



