472 Mr. Hinds on Climate in connexion 



heat and light of the sun. Ingenhouz was the first to observe 

 this prejudicial effect of light, and the circumstance was soon 

 confirmed by Sennebier. 



IV. Soil. 



There are several circumstances which favour the conclu- 

 sion that soil is of secondary importance in its influence on 

 the vegetable kingdom. 1. In those climates where the heat 

 and moisture of the atmosphere are in excess, and vegetation 

 puts on its gayest forms, it is not unusual to see the roots of 

 the loftiest trees of the forest exposed in the beds of moun- 

 tain torrents, where they have been left bare by the sudden 

 rush of water in the rainy season. Often trees of the greatest 

 vigour shoot upwards from the fissures of hard rocks, the 

 roots penetrating the crevices, and to every appearance with- 

 out the means of communication with anything like soil. 

 2. A considerable number of plants live on the surfaces of 

 others, without drawing the least portion of nourishment from 

 them. These are the truly epiphytic kinds, and include nu- 

 merous species of Orchidacece, Aroidece, Bromelia, Tillandsia ; 

 with many ferns, mosses, lichens and fungi. Their depend- 

 ence seems placed chiefly in the atmosphere for the means of 

 existence ; though it is no doubt true, that when large trees 

 become a good deal covered with many of these plants, a 

 quantity of refuse vegetable matter collects round the points 

 of attachment, and is made available by the plants themselves. 

 The manner in which the bases of the leaves in Bromelia and 

 Tillandsia sheath over each other so as to form a cup, enables 

 them to retain a quantity of water for a long time, and the 

 falling leaves, portions of broken branches, flowers and fruits 

 that have been shed, all tumbling in and mixing together, 

 form a very turbid but nutritive mixture. Few, I imagine, 

 will not sympathize with Dampier, when in a similar situation, 

 who informs us, that, when wandering in the woods and 

 parched with thirst, he was frequently in the habit of opening 

 a channel with his knife in the lower part of these plants, and 

 thus obtaining a good supply of water. Frequently dead beetles, 

 drowned ants, and many other insects are floating on the sur- 

 face, all which may make a very serviceable beverage for the 

 vegetable kingdom, but one httle likely to be palatable to 

 man. 3. That plants generally are not conspicuous for their 

 attachment to particular soils, is manifest from the number 

 which will thrive in the uniform circumstances of a botanic 

 garden ; here species which have been assembled from a va- 

 riety of situations are placed side by side, and grow so well, 

 that there is every inducement to believe the nature of the 



