Luther — Economic Geology of Onondaga County. 269 



quantity of what was supposed to be ordinary quicklime, from the "blue 

 lime" beds of the Helderberg escarpment persistently refused to slack on 

 the application of water, as required in the usual process of making mortar. 

 This circumstance led Judge Benjamin Wright and Canvass White, civil 

 engineers employed on the canal, to thoroughly examine the rock strata and 

 they employed Dr. Barto, of Herkimer county, to assist them in a series of 

 experiments which resulted in the knowledge of the great value of hydraulic 

 cement, and of the method of preparation and the character of the strata 

 from which it is derived. It was first used on the canal in 1819, and sub- 

 sequent to that year all of the masonry on this construction was laid in 

 water-lime. It immediately took rank as an important resource of Onondaga 

 county and maintains that position to the present time. 



The quarries from which the cement rock is taken, are usually located 

 near the top of the Helderberg escarpment, where the superjacent beds of 

 limestone are comparatively thin. After these have been removed and utilized 

 as building stones or made into quick-lime, the hydraulic limestone is loosened 

 by blasting-powder and heavy bars, and broken into pieces of as nearly uni- 

 form size as possible and convenient for handling, then loaded on cars or carts 

 and hauled to the kilns. The kilns are egg-shaped wells, ten feet in diameter at 

 the top, twelve feet in the middle, three and one-half feet at the bottom, and 

 twenty-eight to forty-two feet deep, with an opening at the bottom, from 

 which the contents can be taken out at will. There are usually several kilns 

 built in an embankment of very heavy masonry, so constructed against a 

 hillside that the raw material can be conveniently conveyed there from the 

 quarry, and burned lime easily removed from the bottom of the kiln. 



Great care is used in the selection of the material and the construction of 

 the kilns, to enable them to withstand the long continued tierce heat. Onon- 

 daga limestone is most commonly used, Oriskany sandstone occasionally. 

 Generally, but not always, a lining of tire-brick is put in. When a kiln is 

 ready to be filled, a cord of dry, hard, four-foot wood is put into the bottom 

 and covered four inches deep with coarse anthracite coal, then a layer one 

 foot thick of the limestone, succeeded by another layer of coal, partly coarse 

 and partly fine. This is repeated till the kiln is tilled t<> the top. which 

 requires about ten tons of coal and fifteen cords of stone, equal to 1, ."><><) 

 bushels of lime. Then the tire is started at the bottom, and gradually works 

 its way upward until the whole mass is glowing with heat. After two or 

 three days the gate or door in the bottom is opened, and through it the lime, 

 now in ragged clinking masses, is drawn to the amount of '27)0 to 'M)0 bushels 



