70 
Skene. — The Acidity of Sphagnum and its 
Table III. 
Salt. 
Sphagnum. 
Peat. 
Sodium chloride . . 
0*0122 
0*0199 
Potassium sulphate . 
0*0207 
0*0253 
Calcium chloride . 
0*0144 
0*0162 
Ammonium sulphate 
0.0253 
0*0300 
Potassium iodide 
0*0119 
0*0120 
Sodium nitrate . . 
0*0224 
0*0205 
Sodium sulphite 
0*0778 
OTO92 
Sodium formate 
0*0706 
0*0852 
Sodium butyrate 
0*0675 
0*0836 
Sodium salicylate . 
Ammonium acetate 
0*0491 
not determined 
0*0563 
Calcium acetate 
0*0840 
0*0I090 
It will be seen that the two substances possess the property in common, 
and that, while the peat is slightly more active, the two sets of figures run 
so closely parallel that it would seem permissible to refer the property to 
the possession of some common compound. 
Baumann and Gully fix on the fact that the Sphagnum and peat are 
able to break up such salts as sodium chloride, liberating the acid and 
removing the base. They say that if an acid is responsible, then we must 
suppose that an insoluble organic acid is capable of breaking up so strong 
a combination as sodium chloride, producing an insoluble sodium salt, and 
liberating hydrochloric acid. This they consider impossible. They believe 
that the reaction is due to the presence of colloidal substances which adsorb 
the base and set free the acid. They adduce the following considerations 
in support of their theory: 
1. The conductivity of Sphagnum 1 is very low, only about i/io of 
that of a solution of acetic acid having the same solvent action on tricalcium 
phosphate. 
2. When Sphagnum acts on a salt the amount of acid liberated is, 
relatively to the amount of Sphagnum employed: 
(a) Less as the concentration of the solution is decreased ; 1 2 
(b) Greater as the amount of Sphagnum acted on by a constant volume 
of solution, is decreased. 
In the case of the combination of an acid and base giving an insoluble salt, 
the amount of salt formed would be directly related to the amount of the 
reagent present in smaller quantity, in this case of the Sphagnum . 
3. The activity of Sphagmim decreases slowly when it is kept; this 
would correspond to the slow change in surface of a colloid. 
1 The alternative ‘ peat ’ is implied. 
2 For tricalcium phosphate aberrant results were obtained: these do not agree with the results 
of Tacke and Siichting, or of Fleischer (Landw. Jahrb. 1883, vol. xii, p. 164) : it would seem that 
none of these investigators has paid sufficient attention to the complicated nature of this particular 
reaction, and that slight differences in method may be responsible for the discrepancies. But for 
chlorides a maximum absorption was found in normal solutions. 
