J. M. Ordway on Waterglass. 161 
time on the end of an iron rod,—and on stirring, the sulphate 
will be seen to separate, as a thin liquid, from the past, silicate. 
The workman should then throw in a pound or two of coal and 
ing sulphurous acid, but soon subsides again. A second or third 
addition of coal may be necessary, and some practice and tact 
* The plan of havi d lower than the grate may be highly recommended 
ge thei [ Ms slaterial te tec! 3 , that becomes fluid in . Biot heat. Thus 
4+ have found it to be dvantageous in smelting artificial 
ron borings and coal. pay saaoeuuliaien a high arch, but when the arch me 9 
+ When soda ash is used instead of the sulphate the same furnace affords six _ 
_ Somewhat larger charges in 24 hours. seas 
Am. Jour. Sci—Srcoxp Sxrims, VoL. XXXII, No. 95.—Sert., 1861. 
21 
