4 



EXPLANATION OF TABLES OF ANALYSES 



In Table I the column headed "Proportion of total oxides as carbonates" 

 shows the extent to which the lime and magnesium combined with the carbonic 

 acid in the air in the effort to revert back to the original form when taken from 

 the quarry. Lime or magnesium not in the form of carbonate is present either 

 in the caustic form or as a hydrate (water-slaked lime). 



The column headed "Pounds of effective oxides in one ton" gives the calculated 

 calcium and magnesium oxides contained in one ton of the product, it being 

 assumed that all of the lime and magnesium from this source will become avail- 

 able during a period of five years. The calculations found in the column headed 

 "Cost of 100 pounds of effective oxides in car lots f.o.b. plant" were based on 

 prices furnished by the manufacturers with the exceptions which are noted 

 in footnotes. In estimating the probable cost on a delivered basis, freight costs 

 from shipping point to destination where used must be computed. 



In Table II the column headed "Pounds of effective oxides in one ton" is 

 calculated as in Table I, except that the degree of fineness of the limestone is 

 taken into consideration. It is assumed that the oxides contained in that portion 

 of the product which will pass through a 20-mesh sieve all become effective 

 within a five-year period, and what are contained in that portion which fails 

 to pass through the 20-mesh sieve will be only 50 per cent effective during the 

 same period. 



In both tables the figures in parentheses following the brand name show the 

 number of samples collected and inspected. 



