174 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The following specimens, weighed when gathered, were left without 

 water for a day. They were then weighed again, their losses per cent, 

 being given below. They were then partly immersed as before. They 

 were once more weighed on the following day, after having been carefully 



dried. 



OoryltLS Arellano, first loss per cent. 49*00, subsequent gain per cent. 57*20 

 Berber is Aqu if olium „ „ 37*64 „ „ 13*42 



Sijringa vulgaris „ „ 35*70 „ „ 18*80 



In these three the foliage had faded to a considerable extent ; conse- 

 quently the gain per cent, is very large. 



Hedera Helix, first loss per cent. 10*76, subsequent loss per cent. 7*30 

 Bex aquifolia „ „ 13*93 „ „ 9*04 



In these two the transpiration exceeded the absorption'; but the 

 smaller loss after immersion, as compared with that before it, indicates 

 that these coriaceous leaves had freely imbibed water. 



Buxus semper vir ens, 



first loss per cent. 23*95, gain per cent. 



610 



Aucuba japonica 



17*28 



4*58 



I'runus Ijawocerastis 



22-35 



1212 



I'noius lusitanica 



18-49 



•36 



Thuja, sp. 



14*93 



6*84 



Cedrus Deodara 



26*85 



45*57 



Taxus baccata 



20-92 



25*46 



Viburnum Tinus 



38-15 



44*21 



In these specimens the gain varies according to the amount of foliage 

 exposed to the air, and the consequent loss by transpiration, all tending 

 to establish the general conclusion that the retention of freshness visible 

 to the eye, or the variable amount of loss or gain as proved by the 

 balance, depends solely upon the respective conditions of " supply and 

 demand." 



7. On the Absorption of Dew. 



In the following experiments the leaves were gathered between 4 and 

 5 o'clock in the afternoon of September 10. They were then exposed at 

 an open window to the full light of the sun until it set. After two and 

 u hall hours the herbaceous leaves showed obvious signs of loss of water, 

 bavin In come more or less flaccid. The lo<s was not visible in the case 

 of the coriaceous leaves. They were all weighed at 7 p.m. A bright 

 moonlight night followed, and an exceedingly heavy dew began to form 

 at 7 P.M. The specimens were all spread out upon a grass-plot. At 

 7 \.m. on the 11th, before the sun was visible, in consequence of a very 

 heavy mist, the specimens were carefully dried with a soft cloth so as to 

 remove all trace of dew with which they had been entirely covered. They 

 were then weighed. In every case there was an actual gain, as seen in 

 the following table. But, besides the proof afforded by the balance, the 

 ^t> ins and leaves had perfectly recovered the freshness and rigidity which 

 fch< y had lost on the provious evening. It was quite impossible for the 

 dew to have been absorbed by the cut ends of the stems. 



