29 



then be found to contain for every 17 moleonles of lime 100 molecules of 

 magnesia, while in the straw there will be found fully 224 molecules 

 of lime for every IOC) molecules of magnesia. The leaves of Phaseolits 

 vulgaris contain in comparison to the magnesia content four times as 

 much lime as the seeds, and those of Brassica napus seven times as 

 much. The proportion of magnesia to lime in tobacco leaves was found 

 to be, on an average, as 1 to 5. The proportion of these constituents in 

 the flowers is also diftereut from that in the leaves. For example, 

 in the case of Humulus lupulus there was found in the— 



Flowers 1 P^rt magnesia to 2 parts lime. 



Leaves 1 part magnesia to 6 parts lime. 



On comparing the underground parts of the plants with the leaves, it 



was also found that the latter contain more lime. For example, it was 



observed in — 



Daucus carota, roots 1 part magnesia to 2. 5 parts lime. 



leaves 1 part magnesia to 14. parts lime. 



Solanitm tuberosum, tubers 1 part magnesia to . 6 part 1 ime. 



leaves 1 part magnesia to 6. 1 parts lime. 



Very great ditferences are revealed also in the comparison of the 

 wood with the seeds in this regard, the lime content being relatively 

 increased in the wood : 



Abies pectinata, seeds 1 part magnesia to 0. 09 part lime. 



■wood 1 part magnesia to 4. 62 i)art8 lime. 



Finns sylvestris, seeds 1 part magnesia to . 12 part lime. 



■wood 1 part magnesia to 1. 60 parts lime. 



For the fruiting year of a beech tree 150 years old, E. Weber > sev- 

 eral years ago made some interesting observations on the migration of 

 magnesia. He found that magnesia as well as nitrogen migrates from 

 the trunk to the points of seed formation, and in a smaller measure 

 also sulphuric and phosphoric acids do the same. The decrease of the 

 magnesia in the wood extended to ninety annual rings. The wood of 

 the tree was analyzed in zones of thirty rings eacli. The percentage 

 of lime and magnesia in the ash are given as follows, as is also for 

 comparison the composition of a beech tree of the same age which 

 had grown near by, but which bore no fruits that year: 



Lime and magnesia in afruitinij beech and in a control beech. 



Forstl. Naturw. Zeitschr., 1892. 



