ABSORPTIVE POWER OF THE SOIL. 845 
replaces those ranged to its left in the above series, but 
none of those on its right. Way remarks, that “ of course 
the reverse of this action cannot occur.” Liebig (Ann. der 
Chem. u. Pharm., xciv, 380) drew attention to the fact 
that Way himself in the preparation of the potash-alumi- 
na-silicate, demonstrated that there is no invariable order 
of decomposition. For, as he asserts, this compound may 
be obtained by digesting either the lime-alumina-silicate, or 
soda-alumina-silicate in nitrate or sulphate of potash, when 
the soda or lime is dissolved out and replaced by potash. 
Way was doubtless led into the mistake of assuming a 
fixed order of replacements by considering these exchanges 
of bases as regulated after the ordinary manifestations of 
chemical affinity. His own experiments show that among 
these silicates there is not only no inflexible order of de- 
composition, but also no complete replacements. 
The researches of Eichhorn, ‘‘ Ueber die Einwirkang ver- 
diinnter Salzlésungen auf Ackererde,” (Landwirthschaft- 
liches Centralblatt, 1858, ii, 169, and Pogg. Ann., No. 9, 
1858), served to clear up the discrepancies of Way’s in- 
vestigation, and to confirm and explain his facts. 
_As Way’s artificial silicates contained about 12 per cent 
of water, the happy thought occurred to Eichhorn to test 
the action of saline solutions on the hydrous silicates 
(zeolites) which occur in nature. He accordingly insti- 
tuted some trials on chabazite, an abstract of which is 
here given, 
On digesting finely pulverized chabazite (hydrous sili- 
cate of alumina and lime) with dilute solutions of chlo- 
rides of potassium, sodium, ammonium, lithium, barium, 
strontium, calcium, magnesium, and zinc, sulphate of 
magnesia, carbonates of soda and ammonia, and nitrate 
of cadmium, he found in every case that the basic ele- 
ment of these salts became a part of the silicate, while 
lime passed into the solution. The rapidity of the re- 
placement varied exceedingly. The alkali-chlorides re 
15* 
