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 have combined with the carbonic acid 

 in the air in the effort to revert back to the origmal 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 hj^drate (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 Avill become available during a 

 period of five j'ears. The calculations found in the last double column, headed "Cost 

 of 100 pounds of effective oxides in car lots f. o. b. kilns," were based on prices fur- 

 nished 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, save that the degree of fineness of the limestone is taken into considera- 

 tion. It is assumed that the oxides contained in that portion of the product which 

 will pass through a 20-mesh sieve are effective during a five-year period, and what is 

 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. 



