THE FLORAL WORLD AND GARDEN GUIDE. 



133 



radiation. In fact, ground frequently 

 hoed becomes warmer from its more 

 ready absorption and conduction 

 downwards of solar neat, so that the 

 roots of the plants are kept warmer 

 and moister in broken ground than in 

 close hard ground, and therefore the 

 vigorous growth of vegetation is 

 promoted. Prominence has been 

 given in English journals to the con- 

 clusions of M. Duchartre on the 

 disposition and effect of dew upon 

 plants, as reported on in the last 

 number of the " Annales des Sciences 

 Naturelles ;" and for the experiments 

 so carefully conducted and so in- 

 geniously devised M. Duchartre 

 deserves the highest praise. But 

 in the conclusions there is nothing 

 new. We have ourselves frequently 

 indicated to gardeners that the chief 

 benefit of dew to plants arose through 

 its absorption by the soil for the nou- 

 rishment of their roots. In the Floral 

 Wokld of July, 1859, we find the 

 following, just to the point : — " Look 

 at a piece of loam, baked hard with 

 heat, planted with dahlias, cabbages, 

 or what not ; not a drop of water, or, 

 if plenty, the labour of carrying and 

 delivering would be too much to 

 think of. Use the hoe over that piece 

 of ground, as if you would let out the 

 last drop of moisture from the soil by 

 evaporation. But, presto ! you have 

 conquered the enemy. Next morning 

 the plants look fresher, they grow 

 above ground and below ground, and 

 get substance, when it appears as if 

 the heat ought to kill them." It 

 comes to this, that if you cannot soak 

 the ground with water, you have only 

 to break the surface and it will soak 

 itself. The more heat by day the 

 more dew by night, the more cloud- 

 less the sky the heavier the deposi- 

 tion of moisture between sunset and 

 sunrise. 



M. Duchartre's experiments show 

 that if the dew is allowed to settle 

 on the leaves of plants, and not on 

 the soil in which their roots are, they 

 gain nothing in weight, whereas 

 when the dew is allowed to condense 

 on the soil tbey gain considerably. 

 A plant weighing 969 50 grammes was 

 so placed that the soil in the pot had 

 the full influence of the dew, and it 



had gained in weight when the dew 

 was removed from the leaves 13 

 grammes. Another weighing 1034 9o 

 grammes gained 6 90 grammes. In 

 other experiments where the soil in 

 the pots was hermetically sealed, 

 there was not only no gain of weight 

 by dew, but a positive loss, which 

 goes very far to prove that plants do 

 not absorb much moisture by their 

 leaf surfaces, and may perhaps give a 

 new turn to our ideas on syringing. 

 But let that pass, we will not throw 

 away the syringe yet awhile. Plants 

 with hard waxy leaves, such as 

 Veronica Lindleyana, certainly da 

 not absorb much, but they need to 

 be kept clean ; and plants with 

 porous leaves, like the vine, do absorb 

 largely, and may be kept alive for 

 some time with the roots dried up, if 

 the leaves are frequently wetted. 

 But the hoeing is the matter we wish 

 our readers to think about and act 

 upon. The hoe is an irrigator of as 

 much value to the English gardener 

 as the Shadoof is to the wretched 

 cultivator of millet on the banks of 

 the Zab or Tigris, and where people 

 are wasting their strength in convey- 

 ing hogsheads of water which are 

 often more harm than good, the 

 labour might in most cases be saved, 

 the ground kept clean at the same 

 time, and the plants encouraged to 

 push their roots about in search for 

 nourishment by the use of the hoe, 

 and the hoe alone. Take notice of a 

 rhubarb leaf; the midrib forms a 

 deprecsed groove, and the leaf slopes 

 up on each side of it, somewhat in the 

 fashion of the two sides of a wooden 

 water-shoot. The upper surface of 

 the leaf-stalk is channelled too, and 

 all night long the leaf distils dew 

 from the atmosphere, the water 

 trickles to the midrib, and thence 

 fiuds its way by the channel of the 

 stalk direct to the heart of the plant, 

 for the benefit of its roots and rising 

 leaves. This is the way nature 

 makes almost every plant its own 

 irrigator: we must co-operate with 

 nature, and by the use of the hoe 

 assist the soil also to drink freely of 

 the dew of heaven, that we may 

 enjoy thereby the fatness of the 

 earth. 



