234? Mr. Ring's further Observations on ultimate Analysis. 



The liquid which I obtained by gentle distillation from the 

 roots of the hyacinth *when young I found to be constituted as 

 under :* 



Carbon •250 



Hydrogen 35 



Nitrogen *158 



Water 99-557 



100- 

 It had a specific gravity of 1001 '6, that of water being 1000. 

 The dry solid matter of the same young roots examined in 

 the mass was constituted of 



Carbon 4-0*8 



Hydrogen 1*4? 



Nitrogen 5'5 



Residual 3*5 



Water 48*8 



100- 



Thus showing an excess of hydrogen in these young roots ; 

 but when the plant is full grown, I find the hydrogen pre- 

 dominating in the spiral vessels only\. 



The valuable suggestions which I have received from the 

 Rev. J. B. Reade of Peckham, have enabled me to prove that 

 which appears to be a principle in vegetable physiology, viz. 

 that the chemical composition of the roots of plants varies 

 with the season and the stage of their growth, and that the 

 constituent parts of the full-grown roots have their own pe- 

 culiar chemical characters. 



In the analysis both of liquids and solids by the method 

 now proposed, it must be observed that the amianthus which 

 is used for condensing the vapour of water condenses also 

 carbonic acid gas, and this too in quantities proportionate to 

 the quantity of water condensed in the amianthus. The 

 quantity of carbonic acid gas so condensed varies also with 

 the mode of conducting the experiment. Every analyst must 

 find out this quantity for himself. By my mode of conduct- 

 ing experiments, the gas which remains in the analysing tube 

 is equal to about -j-^^j of the interstices of the tube which are 

 not filled up. This I ascertain by driving off the condensed 

 water and collecting the gaseous products over mercury in 

 the usual way. 



A very satisfactory mode of proving the correctness of the 

 analysis of any compound is to repeat the experiment, and 



♦ My best analysis of this and similar liquids can only be considered as 

 an approximation to their real constitution. 

 f See page 422 of the last volume of Phil. Mag. 



