438 TRANSACTIONS OF THE 



retary, may answer well where they are excluded from the direct action of 

 the sun's rays, hut we know hy experience that paper coated with bitumen 

 will not answer for covering roofs, where it would he subject to such action, 



Mr. Seeley. — The cause of failure in the case of roofs is not to be found 

 in the use of bitumen, for some kinds of bitumen will staud well, while 

 other kinds will entirely fail, so different in quality are various specimens. 

 Perhaps, if it were mixed with India rubber it would stand better. 



Mr. Veeder. — Bitumen should, when laid on roofs, be sprinkled with 

 sand, after which one or two extra coats of the bitumen should be given. 

 An excellent artificial bitumen is left as a residuum from the distillation 

 of coal oil. It does not volatilize at 600'^ Fahrenheit, consequently it 

 resists the action of the sun. It has no taste. 



Mr. Seeley.- -The refuse from purifying oils with sulphuric acid, is a 

 thick and very tough tar, well adapted for such uses. 



Mr. Veeder. — The refuse from candle works is imported and distilled 

 to obtain oil, by Mr. Everitt. Now if a use can be found for the refuse 

 from gas works it will also become valuable. 



Mr. Seeley. — I was the first person who distilled that substance, having 

 done so about five years ago. I filed a caveat, and almost immediately 

 afterwards the price of the material rose. 



Professor Renwick stated that he was glad that he could speak on the 

 subject of asphaltum from practical experience, rather than from scientific 

 theory alone. He had been engaged for the whole of one of his vacations, 

 more than twenty years since, in the search for a material capable of uni- 

 ting with bitumen after the manner of the limestone of Seyssel. It was a 

 fact, not to be predicated from mere theory, that of all earthy substances, a 

 carbonate of lime, already impregnated with bitumen, unites most kindly 

 with that substance, whether native or the residuum of distillations. He had 

 found such a limestone at Caledonia, Genesee county. New York, and, on 

 trial, it, when in combination with the bitumen of the West Indies, 

 appeared to possess all the good qualities of the asphalte of Seyssel. It 

 Was tried the succeeding summer upon one of the areas of the Merchants' 

 Exchange, and, according to his recollection, appeared to stand the heat of 

 summer well, but cracked to pieces when the cold became intense. He had 

 observed the same in relation to the asphalte of Seyssel, when laid in warm 

 weather in New York, and that, if laid in cold weather, it became soft in 

 summer. In his opinion, therefore, except for covering vaults, where the 

 temperature is nearly uniform, no bituminous compound can be used to 

 advantage upon roofs in the climate of New York, while in the more equa- 

 ble climates of Paris and London it can be and is successfully used for 

 that purpose. 



Mr. Stetson wished to learn what the common price of the metal alumi- 

 num was. 



Mr. Butler stated that in Paris it was sold for thirty dollars a pound. 

 Also that it would not burnish, but would always present a gray color. 



Mr. Tillman considered that aluminum was likely to be used extensively 



