CULTURE OF THE GRAPE-VINE. 



453 



be stated on general principles, that when the vine is in a growing state the 

 air must be keep moist, more particularly in the evenings and during night. 

 This may always be effected by syringing the plants before shutting up the 

 house in the afternoons, and when the sun goes off a south wall, and by 

 watering the soil. When the fruit is ripening, the air should be drier ; not 

 only because growth being completed, less moisture is wanted, but because 

 excess of moisture, either in the soil or in the atmosphere, is known to be 

 injurious to the flavour of all fruits. 



956. The, soil in all countries where the vine is cultivated successfully is 

 dry, and experience has proved that it admits of being enriched to an 

 almost unlimited extent. The, temperature of the soil may be determined 

 from general principles to be a degree or two higher than that of the atmo- 

 sphere ; "therefore the most favourable climate for the vine lat. 85% which 

 passes through Syria, will have a mean terrestrial temperature of 67^. In 

 spring, when vegetation begins in the vine, it may be estimated at not lower 

 than 60°. By the time the blossom expands it will have reached 70°, or 

 nearly so ; and 80° will certainly be within the limits of its summer tem- 

 perature." — {Penny Cyc, art. Grape-Vine.^ "The mean temperature of 

 the earth in the climate of London is about 51°, from which that of spring-- 

 water differs little throughout the year. In winter, when early forcing of 

 the vine is commenced, the border in which the roots are extended will 

 sometimes be below 40°, and if we even say 45°, whilst the vine has its 

 branches and blossoms in a temperature of 7 5°, still we have a disparity of 

 30° ! These conditions are not by any means transient, for the earth retains 

 its state of winter cold till late in the spring. In summer, from the greater 

 length of the days at this season than in more southern latitudes, the earth 

 acquires a tolerably high and nearer corresponding temperature ; but before 

 this occurs the crop of grapes has received checks which more favourable 

 circumstances cannot remedy. To this disparity of temperature between 

 the root and the top of the vine may be certainly ascribed the had setting^ 

 spotting, and shrivelling of grapes." — Ibid. A writer in the Gardeners 

 Magazine.) vol. xiii. p. 16, has forcibly illustrated the importance of a cor- 

 responding atmospheric and terrestrial temperature, and he concludes by 

 recommending all exterior vine-borders to be securely thatched, so as to 

 exclude all rain and melting snow during winter and spring, and not to 

 remove the covering till the temperature of the natural rain which falls on 

 the border is 60". The thatching, he says, if put on in time in autumn, 

 will preserve a temperature in the soil through the winter of between 45" 

 and 50°, and the rain falling on the soil at a temperature of 60° will part 

 with 10° of its heat, and, after moistening the soil, pass off by the drainage. 

 Repeated showers at an increased temperature, aided by the effect of the 

 sun, will gradually raise the temperature of the border from 45° or 50° to 

 75° or 80°, according to the warmth or coldness of the summer. The process, 

 he says, may be greatly accelerated by stirring the surface, or inverting it by 

 digging where it has been, well heated by the sun's rays, so as to turn up a fresh 

 portion to their influence. A considerable degree of heat might thus be as it 

 were " worked in," and the remainder of heat required would be effected by 

 the percolation of showers and the direct influence of the sun. The effect of 

 melting snows and early spring rains, at probably 40°, in cooling the soil, 

 shows the necessity of choosing a porous and naturally thorough-drained 

 soil for vineyards in countries having cold winters ; because as it is iniprac- 



