324 Transactions of the American Institute. 



extent, and that it usually succeeds well, and gives excellent satis- 

 faction. 



The report alludes to the fact that this kind of roofing is some- 

 times liable to crack when it is not properly put on; and in some 

 instances, complaint has been made that the effluvia arising from 

 the coal tar with which the flour is mixed, is very disagi*eeable; 

 and in a few instances complaint was entered against this roofing 

 where the rain water is collected, as the coloring matter in the tar 

 will color the water. The report was accepted, and the committee 

 were discharged. 



I\Ir. Solon Robinson. — Although there have been failures in 

 making roofs of this material, they are all traceable to causes that 

 do not militate in the least against the value of plastic slate, which 

 indisputably does make a perfectly water-tight roof, and what adds 

 to its value, one that is actually fire proof. I have the oldest roof 

 in this vicinity upon pai't of my house in Westchester county. 

 After more than two years' trial, I do not hesitate to say that I 

 would not exchange it for any other known roofing material. I 

 believe it should, and probably will supersede all other materials. 

 I believe no roof, properly made of this material, ever failed. In 

 addition to what was stated in the report, the committee find that 

 plastic slate is coming into use more rapidly than ever has before 

 almost any other new article or invention. We find recent dis- 

 coveries and improvements in the use of plastic slate exceedingly 

 promising of benefit to the public. It has been used successfully _ 

 to stop the tide out of cellars, where everything else had failed. 

 It is now applied to felting, so as to make portable, ready rooting; 

 and sheets of slate have been cheaply constructed, which are better 

 than those from the quarry', because flexible. Experiments are 

 now in progress, which promise a light, cheap felt for roofing 

 paper, fire and water proof. Favorable reports have been made 

 of the use of plastic slate upon the bottoms of ships instead of 

 copper, as well as for protecting posts and building-timbers from 

 decay. It seems only to need time for men to learn how to handle 

 this new material; and that every new invention has been subject 

 to mistakes and failures; but these should not prevent people from 

 enjoying a valuable discovery, and such we believe this to be, and 

 recommend it accordingly. 



Mr. S. Edwards Todd. — There are a few points not alluded to 

 by the other members of the committee, which I will elucidate. 

 As we desire to treat everything with the greatest possible fairness, 



