Proceedings of tee Farmers^ Club. 325 



we want to give the plastic slate roofing the full benefit of all its 

 advantages. Hearing of so many failures, I have been exceedingly 

 shy of this roofing, until I gave the subject a full and thorough 

 investigation. I have examined numerous roofs, and my doubts 

 are now all removed. I believe that if the tar and the flour are 

 united in proper proportions, a roof can be made as perfect and 

 smooth as a schoolboy's slate. In my investigations, I have found 

 that the law of definite proportions must be observed when mixing 

 the tar and the flour. Tar two years old is much better than tho 

 tar just from the gas works. Tar improves by age. The propor- 

 tions should be difierent, according as the tar is old or new. If a 

 little too much tar be used, or not quite enough, the roof will not 

 solidify so satisfactorily as it will when the tar and flour are 

 mingled in definite proportions. Another consideration which this 

 roofing may have the benefit of is this: I have found that numerous 

 roofs have been made of coal tar, sand and gravel, and they have 

 given wonderful dissatisfaction; and the failure, denunciation and 

 dissatisfaction have all been heaped upon plastic slate roofs, when 

 there had been no flour of slate employed. I have in my mind 

 numerous instances where people condemned plastic slate roofs, 

 after having attempted to make a satisfactory roof of coal tar and 

 sand. Coal tar and sand are very dififerent materials from coal tar 

 and flour of slate. There is another point that I may state for the 

 benefit of this roofing, touching its liability to color the water that 

 js collected on it. I have seen many beautiful roofs in this city 

 made of this material. I was on one very large building covered 

 Avith this plastic slate, the roof of which was and is now as smooth 

 and free from cracks as one unbroken flagstone. When we were 

 examining the roof on a large house, I observed the water standing 

 in the eave-trough, and it appeared as clear as the water floAving 

 from a mountain spring. Previous to my investigations, I would 

 not recommend this roofing to any one. But now, I believe that, 

 if correctly put on, the roofing will be as durable as time; and 

 after the material has solidified, I do not think it will afiect the 

 rain water any more than a roof made of the natural Vermont 

 slate, which is quarried out of the slate beds. 



Mr. J. M. Allen stated that there have been failures in making 

 plastic slate roofs; but such failures were attributable to a poor 

 quantity of tar, or to want of skill in mingling the tar and slate 

 flour in proper proportions. 



