RESULTS 01' EXPERIMEKTS. 



23 



portion. A concentration of 0.0075 normal magnesium sulphate 

 usually produces about the same effect as 0.025 sodium bicarbonate. 

 Therefore one would say that magnesium sulphate is three times as 

 injurious as sodium bicarbonate when in equivalent concentration. 



RESTJLTS OF EXPERIMENTS. 

 RESULTS WITH MAGNESIUM SULPHATE. 



The results obtained for the different varieties with pure solutions 

 of magnesium sulphate are shown by the following table: 



Maximum limit of 

 endurance. 



Name of wheat variety. 



Parts per 

 100,00()uf 

 solution. 



Zimmerman- 



Kharkof 



Padui - 



Kubanka _ 



Turkey -. 



Maraouani - _ 



Budapest 



Preston ._ 



Chul 



Average for all varieties. - 



42 

 25 

 43 

 42 

 56 

 42 

 56 

 28 



40 



Fractional 



part of a 



normal 



solution. 



0.00V5 

 .00625 

 .0075 

 .0075 

 .01 

 .0075 

 .01 

 .005 

 .005 



.00786 



A glance at the aboA^e table is sufficient to show the considerable 

 difference between the varieties in their ability to resist the toxic 

 influence of magnesium sulphate. The least resistant of all the 

 varieties are Chul and Preston, of which about half the seedlings sur- 

 vived in a 0.005 normal solution. Contrasted to these are the two 

 most resistant ones, viz, Budapest and Turkey, surviving equally well 

 in a solution twice as concentrated. 



A comparison of these results with wheat with those obtained by 

 Kearney and Cameron using Lupinus alhus with the same salt will 

 show the great diversity between these two plants. The toxic limit 

 for lupines in a })ure solution was found to be 0.00125 of a normal 

 solution. Accepting the results shown by these figures, magnesium 

 sulphate is four times as toxic to lupines as it is to the Chul and Pres- 

 ton wheats, and eight times as toxic as for the Budapest and Turkey 

 varieties. It may be said in this connection that irom experiments 

 made by Kearney" with maize there is reason to believe that the 

 Graminea^ as a family are much less sensitive to the effect of magne- 

 sium salts than the Leguminosa}. Magnesium sulphate has been 

 found in the course of these experiments with Avheat to be on an 



n Science. X. S., IT : P.SG (100.3). 



