FRANKLIN COUNTY. 631 



The other chief use of the formation is in the manufacture of quick- 

 lime. A large business of this sort is carried on in connection with the 

 quarries referred to above. A notable part of the limestone, viz., eight 

 to ten feet below the Delaware beds, is better adapted to this use than to 

 any other. Too light for building purposes, it would need to be removed 

 at great expense in order to reach the valuable courses below, were it not 

 that it can be used in the lime-kilns with the best results. The analyses 

 already given show the character of the lime produced. As has been 

 already remarked, these quarries furnish the purest carbonate of lime 

 burned, in the large way, in Ohio. It can easily be made to average in 

 the kilns ninety per cent, of this substance ; but the economy of throw- 

 ing in the " spalls," or fragments of the building-stone, instead of leaving 

 them out as waste, reduces the percentage somewhat. The lower courses, 

 it will be remembered, have a larger proportion of magnesia in their 

 composition. The character of the lime is changed, to some extent, by 

 this element, but it is not safe to say that it is injured for all uses. The 

 most approved plastering limes of Ohio to-day are those manufactured 

 from the Upper Silurian formations, the Niagara and the water-lime, 

 which are, chemically, double carbonates of magnesia lime, and of these, 

 the Springfield lime may be taken as a representative. For paper fac- 

 tories, for glass-works, for blast-furnaces, and perhaps for gas-works, 

 the product is to be valued in proportion to its percentage of lime ; but 

 in the wider use of lime, as mortar, a high percentage of this substance 

 is not necessary to insure a high quality. The truth is, that the dif- 

 ferent kinds of limestone yield different kinds of lime, and use has 

 much to do in the value set upon any one. They require different modes 

 of treatment. Each will fail when subjected to the mode of working 

 which the other requires. 



The Columbus lime is a very hot, strong, white lime, that can be made 

 to do the best work of its kind in every respect. To one important use, 

 in addition to all others, to which it has been applied, it seems likely to 

 be put, viz., to use as furnace flux. The furnaces that are already built 

 or are in process of erection in the Hocking Valley, have, it is true 

 layers of limestone in the hills which contain their ore and coal; but 

 these layers are generally light, and it can scarcely prove profitable to 

 follow them into the hills under cover, when limestone of such quality 

 can be so cheaply furnished from the great quarries of Columbus and 

 vicinity. 



Columbus lime, like almost every other lime of Ohio, is burned with 

 wood. Numerous attempts have been made to substitute bituminous 

 coal for wood, in its manufacture. Most of these attempts have proved 



