82 



ECONOMICAL MINERALOGY. 



I cannot refrain from again calling the attention of the pubUc to this subject, as one of more 

 than ordinary importance. When it is recollected that the durability and strength of many 

 of our public works depend upon the water cement employed, it must be a matter of deep 

 interest to those who are entrusted with their superintendence. The water lime now used, 

 being procured from various locahties and manufactured in various ways, cannot possess an 

 uniform character. Furnished as it is at diflferent points on the canal route by contract, it 

 requires more than ordinary care and skill to ascertain the fitness of the several parcels for 

 the works in which they are to be employed. After maturely considering the subject in all 

 its bearings, it appears to me that the only way in which the objections to the present mode 

 can be obviated, and an article of uniform purity obtained, is by having the quarrying of the 

 water Umestone, and the process of its conversion into lime, conducted under the direction of 

 the agents of the State ; when the different parcels even thus produced should be constantly 

 subjected to the severest trials, before being used in any important structures. It is true that 

 the expense of the article might be thus somewhat increased, but this would be trifling in 

 comparison with the advantages which would be secured. For it should be . distinctly ob- 

 served, that while a good water lime is invaluable in the construction of locks, a poor one is 

 worse than useless. The State of New- York is at present, and must be for years to come, 

 so deeply interested in tliis matter, that I cannot hesitate to urge some modification of the 

 present plan upon those who are charged with the direction of her public works. 



TABLE 



Showing the composition of various specimens of Hydraulic Limestones and Cements, from 



the State of New -York. 



II. 



III. 



IV. 



VI. 



VII. 



VIII. IX. 



X. 



XI. 



Carbonic acid, • . • • 



Lime, 



Magnesia, 



Silica, 



Alumina, 



Peroxide of iron, •• 

 Bituminous matter, 

 Moisiuie and loss,. 



25.M 

 13-35 

 15-37 



9-13 



2-35 



i 1-20 



37-60 

 16-65 

 22-75 



13-40 



loss, 

 1-30 



25-00 

 26-00 



28-00 

 i & mag. 

 I 16-00 

 1-00 

 I water, 

 < 2-00 



31-75 

 14-91 



11-50 

 1-50 



39.33 



25-00 

 17-83 

 11-76 



1-50 



[ moisture 



1*50 



27-35 

 16-70 

 8-95 



4-90 



1-75 



i 1-70 



I & moisl. 



I 10-90 

 .39-50 

 22-27 

 10-56 



I 10-77 



40-95 



29-00 

 17-30 



11-00 

 1-50 

 0-65 



39-80 



25-24 

 18-80 



13-50 



1-25 



1-41 



28-79 

 17-70 



0-25 



37-66 

 26-11 

 16-48 



Texture close and compact ; colour bluish, with grey and red spots. 



No. I. From the vicinity of Rondout, Ulster county. 

 Page 78. 



II. Calcined cement from the preceding locality. Page 78. 



III. From the Helderberg, in Albany county. The analysis by Prof. Eaton. Page 79. 



IV. From the immediate vicinity of Schoharie Court-House. Colour drab, resembling the next. Page 79. 



V. Madison county, particular locality unknown, but probably from the vicinity of Chittcnango. Analysis by Mr. H. Sey- 

 bert. Page 80. 



VI. From the vicinity of Chittenango, Madison county. Colour drab, with reddish bands ; fracture conchoidal ; texture 

 earthy. Page 80. 



VII Calcined cement from the preceding locality. Page 80. 



VIII. Calciferous slate of Eaton, from the hill east of the village of Chittenango, Madison county. Page 80. 



IX. From the quarry a mile and a half west of Manlius, Onondaga county. External characters similar to the specimens 

 from Chittenango. Page 81. 



X. Frx>m Grand Island, Erie county. Colour dark drab ; fracture conchoidal. Page 81. 



XI. From Williamsville, Erie county. Resembles the preceding. Page 81. 



