PROPERTIES OF MANURES 241 



acid greatly assists the assimilation of other plant- 

 foods. 



Many plants require soluble sodium silicate, 

 silver-sand, etc., hence, these ingredients are some- 

 times included in our special manures. 



Manganese Sulphate. — Manganese oxide is 

 present in most plants. The ashes of coniferous 

 trees contain from 2 to 10 per cent, of manganese 

 dioxide, rose-trees contain 0*5, vines 0"6, oleanders 

 1*5, laburnums 0'5, sequoias 6, syringas 0"5, beech 

 and chestnut trees 4 '5 per cent, of the same 

 oxide. 



Many years ago Prince Salm-Horstmar stated 

 that manganese, in small quantities, was indis- 

 pensable for the growth of plants ; and it is 

 used as a manure for the Austrian vines. 



Manganese appears to be widely diffused in the 

 organic world. The ashes of the fruit and seeds of 

 cardamoms contain 4 "2 per cent, of manganese 

 dioxide.' It is also present in the ashes of 

 sarsaparilla, hydrastis, rhatany, belladonna and the 

 oak ; ^ and Gu^rin has proved that manganese is 

 universally present, as an organic compound, in 

 the ligneous tissues of trees. The accumulation of 



1 H. Bridges, Chemical News, 1899, vol. 72, p. 154 ; W. W. WUls, 

 Chemical News, vol. 72 ; Guerin, Com/ptes Bendus, t. 125, p. 311. 



2 A. B. Griffiths, Com/ptes Bendus de VAcadimie des Sciences, 

 t. 131, p. 422. 



K 



