AMERICAN INSTITUTE. 461 



directly is not. Is there not, then, the possibility of the wheel slipping so 

 far as the magnetism is concerned ? 



Professor Reuben. — Nicholay, of Nancy, constructed a wheel, the rim of 

 which had one polarity, while the axle, or centre, had the opposite polarity. 

 It is clear that, in this way, magnetism may yet be rendered useful in rail- 

 way locomotion. 



Professor Mason. — Our railroad interests are of such vast importance 

 that it is imperative upon every one connected with them to examine care- 

 fully every thing offering any improvement or economy. Eight years now 

 suffice to wear out our rails, and half that time to destroy our sleepers, and 

 the latter must now be stronger and laid closer than formerly, to prevent 

 the breaking of rails. 



On motion, this subject was laid over until the Secretary shcmld invito 

 Major Serrell to eome forward and explain his plan to the Association. 



The regular subject, "Telegraphs," not having been advertised, a report 

 of the "Committee on Building Materials" was read, which gave rise to 

 the following discussion. 



Mr. Stetson wished for a definition of the term marble, as the meaning 

 given to it in the report is different from what he understood by the term. 



Professor Mason. — Marble is crystalized limestone. 



Mr. Garvey. — In architecture the term marble is applied to all orna- 

 mental stones which take a polish, without respect to their mineralogical 

 classification. Polished granites, limestones, and conglomerates are thus 

 called marbles. 



Mr. Garbanati stated that most of the public buildings are built of lime- 

 stone, hence they stand for centuries, while many of our buildings of sand- 

 stone are crumbling to decay. 



Dr. Stevens considered the magnesian limestones as better than sand- 

 stone for building purposes. 



Dr. Vanderweyde. — In Belgium there is a quarry of sandstone which 

 was used by the Romans, and their works have lasted to the present day. 

 The stone last well when laid in building with the strata in the natural 

 position, but when laid with the strata vertical, the stone soon gives way. 

 The Cathedral of Cologne exhibits in places some evidence of decay, and in 

 observations upon this tine monument of art, we have learned the important 

 lesson that stratified stones must, in their artificial position, conform as far 

 as possible to their natural position in the quarry, 



Mr. Tillman. — The standstones in Northern New York are, doubtless, 

 the best building materials in our State. Limestone, in its composition, 

 has the oxyd of but one metal, while in all other stones there are the oxyds 

 of from three to five metals. Lockport limestone is unsurpassed, and as we 

 go northward from the city, our marbles improve in quality. The Presi- 

 dent reminded us also that as we go down in the quarry the quality of the 

 marble improved. I may add that the Government takes all that can 

 be quarried at Tarrytown. 



Professor Mason. — Caen stone is unfit, for our climate. Already those 



