344 sow CROPS FEED. 



This compound is analogous in constitution to tte 

 zeolites, in so far as it is a highly basic silicate containing 

 water, and is easy of decomposition. It is, in fact, de- 

 composed by water alone, which removes from it silicate 

 of soda, leaving insoluble silicate of ahimina. 



On digesting this soda-silicate of alumina witli a solu- 

 tion of any salt of lime, Way found that it was decom- 

 posed, its soda Avas eliminated, and a lime-silicate of 

 alumina was produced. In several instances he succeeded 

 in replacing nearly all the soda by lime. Potash-silicate 

 of alumina was procured by acting on either the soda or 

 lime silicate with solution of a potash-salt ; and, in a simi- 

 lar mannei*, am,monia and m^agnesia-silicates were gener- 

 ated. In case of the ammonia-compouml, however. Way 

 succeeded in replacing only about one-third of soda or 

 other base by ammonia. All of these compounds, when 

 acted upon by pure water, yielded small proportions of 

 alkali to the latter, viz. : 



The soda- silicate gave 3.36 parts of soda to 10,000 of water. 

 The potash- '" " 2.27 " " potasli " " " " 



The ammonia- '• " 1,06 " " ammonia" " " " 



Way found furthermore that exposure to a strong heat 

 destroyed the capacity of these substances to undergo the 

 displacements we have mentioned. 



From these facts Way, concluded that there exist in all 

 cultivable soils, compounds similar to those he thus pro- 

 cured artificiall}^ and that it is their presence which oc- 

 casions the absorptions and displacements that have been . 

 noticed. 



Way gives as characteristic of this class of double sili- 

 cates, that there is a regular order in which the common 

 bases i-eplace each other. He arranges them in the fol- 

 lowing series : 



Soda — Potash — Lime — Magnesia — Ammonia: 

 and according to him, potash can replace soda but not the 

 Other bases; while ammonia replaces them all : or each base 



