134 



NITRATE OF SODA 



In 1897 * Sjollema found that in many cases, in Holland and Bel- 

 gium, rye was damaged by the application of " nitrate of soda ". On 

 investigation he found that the injury was due to the presence, in the 

 nitrate, of perchlorates. In a number of samples examined he found 

 from 0-14 to 6'79 per cent of perchloric acid (C10 4 ). By direct ex- 

 periment, he showed that potassium and sodium perchlorates retard 

 germination and cause the leaves of plants to which they are applied 

 to become yellow. ^ 



Other investigations have confirmed these results ; e.g., Zaharia, 

 as a result of an examination of 206 samples of Chili saltpetre at Halle, 

 found one sample containing between 5 and 6 per cent, one 3 to 4 per 

 cent, three 2 to 3 per cent, eleven 1*5 to 2 per cent, thirty-nine 1*0 

 to 1'5 per cent, while the remaining 151 contained less than 1 per 

 cent of perchlorate. 2 



Maercker 3 in 107 samples of Chili saltpetre found 



and Crispo 4 gives the following analyses of specimens. of Chili salt- 

 petre from the same cargoes as those which had been observed to have 

 a harmful effect upon plants : 



That sodium perchlorate has an injurious effect on most plants ap- 

 pears certain, but the quantity which is permissible in sodium nitrate, 

 is a matter on which much diversity of opinion appears to exist. 



Zaharia (just quoted) found that solutions containing less than O'l 

 per cent of perchlorate had little or no effect upon the germination of 

 beet, rye and wheat, though oats were affected. The seedlings, how- 

 ever, were injured by even much weaker solutions, oats being most 

 affected, then rye, wheat and lastly barley ; a O'OOl per cent solution 

 had no effect on barley and wheat, but injured oats. He found that 



1 Ann. Agron., 1897, 328; Jour. Chem. Soc., 1897, Abstracts, ii, 585. 

 2 Bied. Zentr., 1899, 511 ; Jour. Chem. Soc., 1899, Abstracts, ii, 799. 

 3 Jahr. iiber Agric. Chem., 1899, 105. 4 Ann. Agron., 1898, 92. 



