28 



With potash salts now selling at from $2.25 to $2.50 per unit, compared with 

 $6 per unit during the past season, it is hoped that during 1920 the manu- 

 facturers may allow for a somewhat larger margin of overrun on this element 

 and thus reduce the large number of deficiencies which have prevailed during 

 the past few years, and which were probably due in a measure to the scarcity 

 and high prices of potash salts. 



LIME COMPOUNDS. 



Thirty-six samples of lime products have been examined. Twenty-eight 

 analyses have been made, representing 26 distinct brands. The guarantees 

 of all of the lime products have been maintained, as a general rule, in a satis- 

 factory manner. The hydrated or slaked limes showed an average of 66.8 

 per cent of calcium oxide and 4.64 per cent of magnesium oxide; lime ashes, 

 an average of 40.11 per cent of calcium oxide and 2.91 per cent of magnesium 

 oxide. Only small amounts of potash (.16 per cent) and phosphoric acid 

 (.24 per cent) were present, which serves to emphasize the fact that this 

 product should be purchased on the same basis as all lime products, — content 

 and cost of calcium and magnesium oxides. Fine ground limestone has tested 

 on the average 43.67 per cent of calcium oxide and 5.65 per cent of magnesium 

 oxide. 



There exists a considerably wide variation in the cost of a hundred pounds 

 of calcium and magnesium oxides from the various forms of lime. Among 

 the hydrated or slaked limes the lowest was 43 cents and the highest was 

 $1.11; with lime ashes the lowest was 67 cents and the highest was $1.02; 

 and with fine ground limestone the lowest was 42 cents and the highest was 

 $3.73. The average cost from all sources, not including " Lime Fertile " for 

 which a ridiculous price has been charged, has been 64 cents. This em- 

 phasizes the importance of securing quotations on delivered products before 

 placing an order for lime. 



With regard to ground limestone, we would note that this is being offered 

 in much finer mechanical condition than formerly. In 1918 the average per 

 cent by weight of the product that would pass a one hundred mesh sieve was 

 71 per cent, while the average for this season was about 81 per cent, some 

 going as high as 98.4 per cent. Limestone as fine as this seems to be quite as 

 effective when used on the soil as the more active forms of lime, provided a 

 sufficient quantity is used to furnish the same amount of actual calcium and 

 magnesium oxides. 



