896 Transactions of the American Institute. 



passed through variously arranged diagonal holes in each piece of 

 wood. 



The Chairman introduced Dr. Ott, who read the following : 



Portland Cement and Portland Cement Stone. 

 By Dr. Adolph Ott. 



Nothing, perhaps, has prevented the extensive use of Portland 

 cement in this country more than the circumstance that most parties 

 engaged in the manufacture of stone, or in the laying of floors and 

 sidewalks, endeavor either to conceal what they are using, or try to 

 make the public believe that the strength of the solidified material is 

 not so much dependent upon the cement as upon some ingredient, 

 generally harmless, which they are using in combination with it. 

 Hence, instead of calling their products simply cement stone, or Port- 

 land cement stone, if made of artificial cement, they are termed 

 " artificial stone." The public, being well aware of the frequent 

 failures following the attempt to introduce an artificial building stone, 

 which, in most cases, has been gotten up by ignorant parties, now 

 evinces a want of confidence in Portland cement stone, because it is 

 offered as " artificial stone." I am far from asserting that no substi- 

 tute may be found for good Portland cement ; but I hold the opinion, 

 and I think with good reason, that all attempts to find such a one have 

 thus far failed. I am also far from maintaining that probably no fur- 

 ther improvements will be made in the application of this cement. 

 On the contrary, by adding other ingredients to it, its strength and 

 durability may be increased, or some other desirable quality may be 

 imparted, and that without proportionally increasing its cost. I am 

 glad to say that such improvements have, in fact, already been made ; 

 but I will not dwell upon them now. 



In the last paper which I read before this association, I endeavored 

 to give you a history of hydraulic cements in general, and to specify 

 the uses to which they have been and may be applied. As my present 

 paper is devoted to only one kind of hydraulic mortar, I can now be 

 more exhaustive, and I shall be able to impart more practical infor- 

 mation. I will first define what Portland cement is ; then describe 

 its properties, the process of induration as now established, the pro 

 perties of the indurated cement or mixtures of cement and inert 

 materials ; and I will then conclude with a review of the uses to 

 which it may be applied. Should I be able to remove some of the 

 prejudices which exist among many of our builders and architects 

 with regard to this cement, and thus lead them to a more extensive 



