COMPOSITION IN SUCCESSIVE STAGES. 217 



The gain during each period was accordingly as fol 

 lows: 



I. Period, 

 II. &quot; 



III. &quot; 



IV. 

 V &quot; 



100 &quot; 100 &quot; 100 &quot; 100 &quot; 100 &quot; 



6. As regards the individual ingredients of the ash, 

 the plant contained at the end of each period the follow 

 ing amounts, the total quantity in the ripe plant being 

 taken at 100. Corresponding results from Bretschneider 

 enclosed in ( ) are given for comparison. 



Silica. uc TcT C Lime Ms**&quot; Pf &amp;gt; ta * h - 

 Per cent. Per cent. Per cent. Per cent. Per cent. Per cent. 

 I. Period, 18 ( 22) 20 ( 43) 23 (23) 80 ( 31) 24 (31) 89 ( 42) 



III! %}&amp;lt;*&amp;gt; II\(W 73J (63 &amp;gt; 3{ &amp;lt; $ ! (73) 9?|&amp;lt; 89 &amp;gt; 



IV. &quot; 93 ( 72) 90 ( 39) 91 (74) 99 ( 74) 84 ( 77) 100 (100) 



V. &quot; 100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 100 (95*) 



The gain (or loss, indicated by the minus sign ) in 

 these ash-ingredients during each period is given below. 



Lime. Magnesia . Potash. 



Per cent. Per cent. Per cent. Per cent. Per cent. Per cent. 

 I. Period, 18 ( 22) 20 ( 42 ) 23 ( 23) 30 ( 31 ) 24 ( 31) 39 ( 42 ) 



iii: }c) *o\&amp;lt;. 2 &amp;gt; 3i!( 40 &amp;gt; iil( 52 &amp;gt; SK 43 i!J( 47 &amp;gt; 



IV. &quot; 23 ( 15) 3S (-5) 18 ( 10) 20 ( 9) 26 ( 4 ) 9 ( 11 ) 

 V. &quot; 7 ( 28) 10 ( 56 ) 9 ( 21) 1 ( 17 ) 16 ( 23) (-5*) 



100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 100 (100) 



These two independent investigations could hardly give 

 all the discordant results observed on comparing the above 

 figures, as the simple consequence of the unlike mode of 

 conducting them. We observe, for example, that in the 

 last period Arendt s plants gathered less silica than in any 

 other only 7| of the whole. On the other hand, Bret- 

 schneider s crop gained more silica in this than in any 



* In these instances Bretschn cider s later crops contained less sulphuric acid, lime, 

 and potash, than the earlier. This result may be due to the washing of the crap toy 

 r^ins, but is orobably caused by unequal development of the several plots. 



10 



