CEMENT.
490
Some thin slabs, measuring x\" thickness, 2" wide, and 6" long, were prepared and set in air, haring special reference to a determination of the absorption of carbon dioxide. Twenty-five per cent of water was used on the mixing. Determinations were made with the material at different ages.
Brand.	Age of sample.	Loss on heating from atmospheric ,temperature to redness.		
		Total.	H20.	co2.
		Per cent.	Per cent.	Per cent. 1.90 3.60 3.62 8.60
				
				
				
		1		
The following determinations were made for the purpose of ascertaining the amount of carbon dioxide absorbed by the reground hydrated cement while drying in the open air at 110° C. This material was taken from the inside portions of 2" cubes which were set in air. Two samples were taken from each of two brands of cement. The first was brought at once to a red heat from atmospheric temperature; the second was dried at 110° C., and then heated to redness. In this comparison the percentages are based upon the weight of the cements after drying at 110° C.
Brand.	Age of cube.	Loss on heating from atmospheric temperature to redness.		
		Total.	H20.	C02.
	Months. 3	Per cent. 12.22	Per cent. 11.36	Per cent. 0.86
Storm King		11	13.70	9.42	4.28
Drying the material at 110° 0. from the atmosphere, the losses in weights were:
Star____________.3.78 per cent
Storm King......5.78 per cent
and then heating to redness the losses were:
Brand.	Age of cube.	Loss on heating from 110° C. to redness.		
		Total.	HoO.	C02.
	Months. 3 11	Per cent. 9.95 8.70	Per cent. 8.33 3.60	Per cent. 1.62 5.10
				
				
The differences in the carbon dioxide of the two sets of determinations are seen to be, for the Star_______________________ 0.76 per cent
and for the Storm King.................................0.82 per cent