NEUTRALIZING EFFECT OF SALTS EMPLOYED. 



41 



about as well as in hydrant water. In order to show to what extent 

 the impurity of the water used Avould affect former experiments, salt 

 solutions of a dilution far below the toxic limits, as already estab- 

 lished, were made, using the water which was but once distilled. The 

 results showed that the toxic element in the water was effectively 

 neutralized by the addition of even minute quantities of any one of 

 the salts used in the experiments. For compai:ison equal numbers of 

 seeds were tested at the same time in the water distilled twice, in that 

 distilled but once (that used throughout the above-described experi- 

 ments), and in dilute salt solutions made up with the once-distilled 

 Avater. 



The following table embodies the results obtained with very dilute 

 solutions of the salts, with distilled water, and with hydrant water : 



Water or solution. 



Water distilled once 



Water distilled twice 



Magnesium sulphate lO.dill normal I'l . 

 Magnesium chlorid {U.Wl normal )«._. 



Sodium carbonate (0.001 normal)" 



Sodium bicarbonate (0.0(C5normal)n . 



Sodium sulphate (0.015 normal)" 



Sodium chlorid (0.015 normal)" 



Hydrant water 



Elongation of roots at the end of a 

 given time. 



First 

 day. 



mm. 



2.2 

 11.1 

 10.6 

 16.8 

 11.3 

 10.6 



8.5 



r.8 



9.4 



Second 

 day. 



mm. 

 2. 

 26. 

 21. 

 30. 

 14. 

 £4 

 22 

 15 

 23. 



Third 

 day. 



mm. 

 2. 

 33. 

 27 

 37. 

 16. 

 31 

 31. 

 19 

 37. 



Fourth 

 day. 



2.2 

 36.3 

 27.6 

 38.2 

 17.8 

 32.4 

 34.8 

 22 

 46 



« The mean toxic limit of all varieties of wheat tested in the presence of the salts here 



employed is shown as follows : 



Parts of nor- 

 mal solution. 



Magnesium sulphate 0. (KI736 



Magnesium chlorid • 00931 



Sodium carbonate • 0109 



Sodium bicarbonate . 026 



Sodium sulphate .0432 



Sodium chlorid . 0542 



A comparison of these figures with the table above shows that from one-third to one- 

 tenth the concentrations of the solutions which represent the limit of endurance of the 

 wheat varieties is sufficient to neutralize the harmful efCect of the zinc present in the 

 distilled water. 



The above table shows that after an elongation of '2.2 mm. during 

 the first day in 'the water distilled once no further growth toolv place. 

 A comparison of that with absolutely pure water (in this case redis- 

 tilled) shoMS that there was some element in the first water which 

 hindered growth and which was not found in the second. This, as 

 the chemical analysis above referred to showed, is probably zinc. 



The results in the dilute salt solutions which were made up with the 

 injurious once-distilled water showed that there Avas no material dif- 

 ference in the elongation made in them and in the checks in redis- 

 tilled and hydrant water. It is not assumed that these dilute solu- 



