1885.] KEW YORK ACADEMY OF SCIEKCES. 59 



wet, vegetable germs had settled upon it and grown, and the rain 

 had washed floating particles of dust into it; and that the 

 arcliitect and tlie builder onghtto have their dues. I asked him 

 if he had witliheld payment from the glazier because his windows 

 had become dirty. His reply was, Well, I will take good care 

 that you don't see those parties; I said, You asked for my opinion 

 on your building, and 1 have given 3'ou a true and honest one. 



Here are for your inspection some pieces of brick taken a few 

 days ago from a uew building on 58th street uear Sixth avenue. 

 You will see it had been painted, and though the paint used was 

 of good, qutility, as shown by its toughness, yet the destruction 

 of the face 'of the brick and the forcing oft" of the coating of 

 paint was wholly due to the caustic alkaline properties of these 

 salts, which were brought to the surface and into contact with 

 the paint by water. This effect can be seen, more or less, almost 

 without an exception, on every brick house that had been painted 

 with ordinary linseed oil paint. And if the paint thus perishes, 

 so does linseed oil when applied alone, though the effect is uotso 

 readily seen. It is therefore neither durable nor effective. How 

 often do we see the paint on a building peeling off the mortar 

 joints and leaving them quite bare, this is due, as I have said, to 

 the action of the lime salts in saponifying the oil. 



Terra cotta shows these salts very much, in some buildings 

 even more than the brickwork. This is noticeable on the new 

 Produce Exchange Building. It is there caused, probably, by 

 the libera], though, perhaps, necessary backing of cement or 

 mortar used to till u]) the hollow spaces behind it, the salts of 

 which come to the surface as before described. 



Stone, especially in contact with brick-work, is damaged by 

 the same cause. The water, no matter how it reaches the cement 

 or mortar in a wall, will permeate through a stone, and bring 

 with it these destructive salts, which quickly eat away the sur- 

 face. 



The late Mr. Francis D. Lee, a well-known architect of St. 

 Louis, Mo., said he believed that the damage to property, caused 

 by the weather and these salts, was at least 1500,000 per annum 

 in that city alone. If that was a correct estimate, who can 

 compute the enormous loss to property owners in such a city 

 as New York ? The fact is, a certain amount of deterioration 

 in house property is looked upon as a matter of course, as some- 

 thing inevitable, and therefore to be borne, like taxation, as 

 l^hilosophically as possible. 



The question before us is, Can this disintegration be arrested 

 or prevented ? Can this natural law of decomposition be stayed ? 

 I believe it can, by shutting out or keeping off that destructive 

 iind ever active agent — water. 



