THE GRAPE VINE. 441 



by the careful experiments of the late Mr. R. Thomson, is for the 

 season of growth 55, for that of ripening 62, and for the season of 

 rest 42. Compare these figures with the temperatures before given 

 for Sicily and Paris, and we find that the natural conditions of the 

 soil of this country, so far as temperature is concerned, are not suitable 

 to the cultivation of the vine ; and hence the reason why it so rarely 

 attains anything like maturity in the open air. 



If, then, the ground temperature of the soil of Britain is unsuitable 

 to the growth of the vine in its natural season, when the solar influ- 

 ences of light and heat are in its favour, it certainly seems unreason- 

 able to expect, when we reverse the order of cultivation and force the 

 vine into growth in the dead of winter rather than in the spring, that 

 it will progress so satisfactorily as it would with a genial natural 

 ground temperature. But we have bottled up in the body of the earth 

 a constant source of heat. We know that beyond the influence of 

 atmospheric changes the temperature of the ground generally increases, 

 and that the deeper we go the greater the heat becomes ; hence the 

 late Mr. Archibald Gorrie, a gentleman of no mean authority in horti- 

 cultural matters in his day, utilized the head of a well by keeping 

 greenhouse plants in glazed frames over the mouth of it ; and Mr. 

 Loudon recommended that pits for the protection of half-hardy plants 

 should be connected with a series of tunnels, through which the ground 

 heat could be carried to protect them. Hence, upon the sandstone 

 formation, the oolite, and even the worked coal measures, it is not un- 

 reasonable to assume the ground temperature is naturally greater than 

 upon the London clay or similar formations. Four years ago, a 

 gentleman on the Peak of Derbyshire had a vinery erected, and, 

 wishing to have grapes grown in the best possible manner, he called 

 to his assistance Mr. Speed, now gardener at Chatsworth, to make the 

 border and plant the vines; and the extraordinary progress which 

 those vines have made is something to call for special remark by re- 

 lating a circumstance which bears upon the subject of ground tempe- 

 rature. In excavating for the border the workmen came upon the 

 mouth of worked coal mines, which was taken advantage of to form a 

 complete drain for the border. We, however, think it is something 

 more than a drain, and that the latent heat, which is ever escaping 

 from the shaft and permeating the drainage substratum of the border, 

 plays a much more important part in promoting the complete luxu- 

 riance of those vines than even the drainage itself. From these vines 

 Muscat bunches 31b. to 51b. in weight are not an unusual occurrence ; 

 while Barbarossas of 91b., and Hamburgs and black Alicantes of propor- 

 tionate size are not unusual. These weights, be it observed, are the 

 result of amateur cultivation, so that larger results might be fairly 

 anticipated from skilled professional management. 



As has been before remarked, vine roots in the valley of the 

 Thames, if not prevented by paving or concreting the bottom of the 

 borders, go at once into the gravel beneath. There they find a con- 

 genial temperature, free from atmospheric influences, and hence the 

 vines may be forced year after year without sustaining much injury. 



