CXJLITJKB UNDER GliASS. 257 



to distingnush between natxiral and artificial heat ; peaohes and all other 

 fiaita and plants will bear more of the former than tlie latter, not only 

 with impunity, bnt at times with benefit. The light accompanying solar 

 heat possibly accounts for most of the difference. Bnt there is also 

 another reason : generally, any sensible rise of temperature from the sun 

 is acoompanled by Tentilatiou ; this sets the whole air of the house in 

 motion, which has possibly an invigorating effect on the blooms and young 

 froit ; whereas a high night temperature is associated with a still 

 atmosphere, hence, possibly,, its enervating infiuence on the blooms and 

 embryo fruit of the peach. High night temperature also draws the young 

 ahoots' and unduly elongates and weakens the leaves ; in a word, it 

 expends the ^ap in a wrong direction and to a wrong purpose, to the 

 -weakening of the vital energies of the tree and consequent loss of the 

 crop. 



During the stoning period it is needful to be cautious. The tree can 

 Hardly be said to have adopted the fruit for good until this process is 

 ■completed. Stone fruits like the peach, that set ten or twenty times 

 more fruit than they are able to bring to maturity, had need be endowed 

 with certain natural powers of thinning. The peach possesses those 

 powers to an alarming extent ; it can throw off most of its fiower buds, 

 refuse to set or swell the major portion of its embryo fruit, and also may 

 cast off any or all its fruits in the stoning. Any excess of heat during 

 these processes augments its thinning powers. An artificial temperature 

 of 60deg; should not, therefore, be exceeded until the stoning process is so 

 far completed that, on trying to out a fruit through with a knife, the 

 stone is so hard as to resist its progress. 



Other means may also be adopted to aid a fuU set and a free swelling 

 of the fruit as well as a careful regulation of temperature., A genial 

 atmosphere, and a free circulation of air are among the more important of 

 these^ In early forcing, too, when no bees or other insects are moving, 

 to distribute the pollen, a, gentle shaking of the trees and the direct 

 distribution of the pollen on to the pistils with a camel's hair pencU are 

 useful mechanical means of helping a free set of fruit. A fine gentle 

 syringing of tepid water serves also to wash the pollen grains into the 

 bvariea,- though heavy syringing or an atmosphere so moist as to lessen 

 the buoyancy of the pollen grains should be avoided. 



After setting more moisture may be used,, sprinkling overhead morning 

 and evening, and the sprinkling of the paths and borders several times 

 a day in bright weather favours the free swelling of the fruit. Early and 

 judicious thinning,- removing all the smallest, worst placed, and 

 unperfectly formed fruit first, also favours and fosters the rapid advance Of 

 the fruit.- A double crop should, however, be left until after the stoning. 



