I 68 TRANSACTIONS OF ROVAI, SCOTTISH ARP.ORICULTURAI, SOCIETY. 



September, the extent of this varying according to the meteoro- 

 logical character of the summer. 



5. This summer rest is succeeded by a new period of greater 

 activity, which is more intense and more prolonged among 

 broad-leaved species than among conifers. 



6. The roots grow quickest at the beginning of summer, the 

 mean maximum for all the oak plants observed being 0*3 9 inch 

 during the early part of July; for maple, 0-35 inch about the 

 end of June or the beginning of July : for Scots pine and silver 

 fir, o'24 inch. 



As live green-manure for enriching exhausted soil in nurseries, 

 the experiments made with various leguminous plants showed 

 that on limy soil, whether binding or not, common peas and 

 beans gave the best results, while white and yellow lupine and 

 hairy vetch ( Vicia villosa) are also good if the soil is very fresh 

 and does not contain more than 2 to 3 per cent, of lime, and yellow 

 lupine is best on soil poor in lime (less than \ per cent.). Com- 

 mon vetch ( V. sativa) was found only to give good results on stiff 

 clayey soil, where it forms a very cheap, though mild manure. 

 Peas are best to use at high elevations, where the climate goes 

 to extremes, and where growing can only begin late. 



Of the other scientific articles, the most interesting is one by 

 Professor Henry of Nancy, on the " Fixation of Atmospheric 

 Nitrogen" by the layer of dead leaves found in woodlands. The 

 investigations were carried out in consequence of the fact that 

 although the poor shifting sandy soil on the dunes of the Landes 

 contains neither humus nor nitrogen, yet the fine crops of mari- 

 time pine now being grown there contain a considerable pro- 

 portion of nitrogen; and the new inquiry was a continuation 

 of similar investigations already published in the Revue in 1897. 



As the result of experiments made with oak, beech, horn- 

 beam, aspen, Austrian pine and spruce, he found — (i) that dead 

 leaves of all kinds, whether alone or mixed with earth, have the 

 property of fixing a considerable proportion of atmospheric air, 

 and especially when they rest on a damp substratum (clay, sand- 

 stone, or lime); (2) that on a poor substratum of pure sand, 

 dead foliage of beech, pine, and spruce either do not (beech) 

 become richer in nitrogen, or else the increase is very slight and 

 insignificant (pine, spruce) — though in no case do they lose 

 nitrogen ; (3) that reliable experiments of this nature cannot be 

 conducted in the forest on account of the action of earth-worms, 



