SOME CONTRIBUTIONS TO PLANT-CHEMISTRY. 



73 



100-00 



It will be seen that the nitrogen, potash, and phosphorus pent- 

 oxide together constitute but 1*22 per cent, of the perfectly dry 

 Beech-scales — a result completely in accordance with the nature of the 

 office performed by these organs in the economy of the plant, and with 

 the season of their appearance. They therefore present, in their 

 chemical composition as well as in their physiological role, a marked 

 contrast to those parts of plants which are concerned in the process of 

 reproduction. 



11. Ulmus campestris. This seems an appropriate place to introduce 

 a few observations on the chemical constituents of the female flowers 

 of the Elm. They offer, so far as the proportions of nitrogen, phos- 

 phorus, and potassium are concerned, a marked contrast to the Beech- 

 scales discussed in paragraph 10 above. They were collected as they 

 fell from the trees on the 22nd of May, 1875, but, being in different 

 conditions of moistness, it was useless to attempt a determination of the 

 water normally present in them. When perfectly dry they were 

 found to give 8-15 per cent, of ash, while the carbonaceous matters 

 burnt off in obtaining this residue contained no less than 3-31 part, 

 of nitrogen. The ash was further analysed, and was found to contain 

 in 100 parts : 



As in the case of the Beech-scales, a clearer idea of the chemical 

 character of the Elm-flowers may be formed by presenting the above 

 results of analysis in a modified form. If we take 100 parts of per- 

 fectly dry Elm-flowers, we find them to contain : 



Carbon, hydrogen, and oxygen . 



Nitrogen 



Potash .... 



Phosphorus pentoxide 



Sulphur trioxide 



Silica .... 



Lime and other ash-constituents 



88-54 

 3-31 

 2-39 



•97 

 1-34 



•40 

 3-05 



100-00 



