Polytechnic Association. 905 



Cost. 

 Messrs. Bandman & Jaffe, manufacturers of cement stone in this 

 city, give the following estimate for the cost of 100 cubic feet of 

 cement, viz : 



87 cubic feet of broken stone and sand $3 00 



13 cubic feet of Portland cement, at $1.25 per cubic foot. . . 16 25 

 Labor 3 50 



Total $22 75 



If hydraulic lime be used instead of cement, say five parts lime to 

 two parts of Portland cement and eight of broken stone and sand, 

 one hundred cubic feet of superior wall can be built, according to 

 close calculation, for $16.75. This is considerably less than one-half 

 the cost of construction with brick and mortar. 



Lintels, sills, caps and arches can all be made at the same time, and 

 with only a slight increase in expense. The partition walls need not 

 be eight inches in thickness ; four or at most five inches will be suffi- 

 cient. 



I will here remark that, by the addition of proper colors, the brown 

 stone of New York city is imitated so accurately in Portland cement 

 stone that the eye can scarcely detect the difference. "With regard to 

 the proportionate cost of these two stones, I would state that the 

 price-list of one of the companies in this city shows that the rates for 

 ashlers, caps, corner-blocks, keys, etc., range from one-half to one- 

 third those usually paid in this market for blocks of cut brown stone 

 of corresponding shapes. 



For such stone, as well as for ornamental work, only fine washed 

 sand is used as an admixture- for the cement. The cost of artificial 

 stone being so much smaller for plain work, it is evident that the 

 difference must be much greater for ornamental work ; for the cost 

 of producing the most elaborate designs, the moulds being once made, 

 is but little more than that of the simplest blocks. When we con- 

 sider that in the ornamentation of our public and private edifices 

 there is no limit except that of design, and that duplicates of cele- 

 brated statuary can be furnished with ease, it is at once apparent that 

 the invention of Portland cement is to sculpture and architecture 

 what photography is to the arts of drawing and painting. 



Uses. 

 With regard to the uses to which Portland cement can be applied, 

 it may be remarked • that they are almost innumerable. For subma- 



