JOUKNAIi OF HOETIOULTUBH AND COTTAGE GABDENER. 



I Jaly 2, 1888. 



effect on the beat at the surface, and it is entirely the latter 

 upon -which the horticulturist is dependant. 



Taking the sun as the one great and only source of heat we 

 necessarily must arrive at the conclusion, that to make the 

 san's heat available in cold and dull periods, it is essential that 

 Ihe heat produced in bright weather be retained, and for its 

 retention it must be absorbed. In general terms, the earth is 

 the only absorber of the sun's rays, but as the sun's rays are 

 direct, and the earth does not present its surface to them ver- 

 ticBlIy in our latitudes, a large per-centage of them is not 

 absorbed, but reflected ; but walls surrounding a garden would 

 giTe a slight increase of temperature, for there will be a greater 

 absorbing, and, consequently, radialing surface. An enclosed 

 space, whatever the material forming the enclosure, will neces- 

 sarily have a higher temperature than an open space, because 

 the heat absorbed is retained longer through the check given to 

 the air passing over the enclosed space ; there is shelter, a 

 greater absorbing, and, of course, a greater radiating surface, 

 and a sensible increase of temperature is afforded plants in 

 the area enclosed. 



It will have been noticed that trees against a wall invariably 

 posh their shoots directly towards the point whence they have 

 the greatest light, or opposite the diiect rays of the sun ; this 

 is commonly termed the shadow of the wall : or rather the 

 growth of the shoots is induced by the shadow being cast in 

 that particular direction. I simpjy name this, so that solar 

 light and heat may not be confounded ; for solar light, however 

 macfa it may contribute to a plant's growth, is not to be treated 

 as heat, though it is simultaneously transmitted. Solar light 

 is the governing power of a plant's growth ; the plant, whatever 

 it IF, will p sh its growth in the directiun of the light, but the 

 light being equally diffused the plant will make equal growths 

 in all directions, subject, of course, to the formation of the 

 plant and its natural habit. Solar heat does not, on the con- 

 trary, appear to have any great influence on a plant's direction 

 of growth. It is the great natural stimulant to activity of 

 growth, and upon it depends the perfection of vegetable life. 

 Plants live and grow for a time without light, but never thrive, 

 and it is in that point of view that we must look at earth heat 

 resnlting from sun heat being absorbed and radiated — absorbed 

 when the surrounding atmosphere-is hotter, and radiated when 

 the atmosphere is colder than the earth's surface. 



The surface of the earth is the culminating point, so to 

 speak, of the extremes of heat and cold. The temperature is 

 greater there than higher in the air upon an average of annual 

 means, for though a thermometer will read 3° or more lower at 

 the ground than at 4 feet from the ground by night, it will 

 read several degrees higher by day than one at -i feet. From a 

 carefnl register of the readings of thermometers at different 

 heights, I find that the temperature progressively decreases 

 with the height, being led to the experiment from noticing 

 some time ago a statement in a contemporary, that at 10 or 

 12 feet from the ground frosts, and especially spring frosts, are 

 never so severe as at or near the surface, consequently the 

 blossoms of fruit trees would be less liable to destruction if tlie 

 trees were cultivated as standards than as dwarfs. Assuming 

 this to be the ease (and it is incontestiblej, there is still a dead 

 loss to the tree of several degrees of temperature by day, and 

 thongh sensibly warmer at night, in cases of sudden frosts, the 

 trees at that height experience a greater loss on account of their 

 not being immediately within the reach of the heat constantly 

 radiated from the earth. The frosts most destructive to 

 fruit-tree blossoms are those which are of long continuance, 

 and in dull periods the blossoms most distant from the earth 

 are those chiefly destroyed, whilst those nearer the earth, from 

 the constant radiation from its surface, enjoy a higher tem- 

 perature, and are very often preserved. Hence Pear and other 

 fruit trees, as dwarfs, almost invariably produce fruit, whilst 

 the same kinds cviltivated as standards do not yield a crop. 

 Indeed, many kinds of Pears that do not succeed as standards, 

 thrive and produce fruit admirably as dwarfs on the Quince, 

 and even on the Pear stock. It is, then, useless grasping at the 

 air for heat ; if we desire it, we must look to the earth. 



The temperature of the atmosphere decreases proportionately 

 upwards ; that of the earth increases downwards. The mean 

 temperature of the earth at 1 foot from the surface is equal to 

 that of the atmosphere at 4 feet. It never in this country, at 

 1 foot from the surface, is reduced to i he freezing point by the 

 cold of winter, at least not in my . xperience, and if we de- 

 scend the temperature is higher, su that nothing further is 

 required than to make an excavation deep enough, and we have 

 at length a temperature sufliciently high for the preservation 



of plants from frost. We must bear in mind that in penetrat- 

 ing the earth we have not only a source of heat but of damp, 

 and that the heat thus secured, or I ought in this case to say 

 attained, will be speedily lost unless it be prevented from ra- 

 diating. We must also bear in mind that plants must have 

 light, particularly when growing, and this is one of the greatest 

 obstacles to the employment of earth heat generally ; but it 

 may be more employed as an agent in the preservation of 

 plants than it has hitherto been, for we have in the earth suffi- 

 cient heat to enable us to winter most, if not all, of the plants 

 known or cultivated as half-hardy, and by that heat we may 

 cultivate successfully the Vine and other fruit trees. With 

 half-hardy plants damp must be avoided, and snfBcitnt pro- 

 tecting material provided to prevent the radiation of the earth's 

 heat and to keep out cold ; whilst with fruit trees the points 

 are to provide a medium for absorbing the sun's rays, and to give 

 the plant the full benefit of the heat absorbed and being always 

 radiated. 



I hope in subsequent papers to show some of the variona 

 uses to which earth heat has been applied, and how mishaps 

 maj- to some extent be obviated. — G. Abbey. 

 (To be continued.} 



JUDGING AT THE ROYAL HORTICULTURAL 

 SHOAV. 

 How can " P." call zoneless Pelargoniums true Variegated 

 Zonals ? The gentlemen named in his letter had an un- 

 doubted right to exhibit ; but that is no reason why they 

 should obtain a prize if they did not exhibit in accordance 

 with the schedule. If the schedule of any society is not to be 

 the guide for both exhibitors and judges, of what use is it? 

 Undoubtedly there is plenty of room for improvement in the 

 arrangement of the schedules of our horticultural societies ; 

 but wiien the schedule remains unaltered up to the day of the 

 exhibition, it is the duty of both exhibitors and judges to abide 

 by it.— J. W. 



ROYiiL HORTICULTURAL SOCIETY. 



Rose Show, Jutw 30/A. — This Exhibition, with which is incoi-po- 

 rated the National Rose Show, was a success, both as regards the 

 nomber of the competitors and the qnaUty of the flowers which they 

 produced at a time when, owing to the gi-eat heat and drought which 

 have so long prevailed, the beauty of a Kose is gone in an hour. The 

 majority of the flowers had snfiered from these causes, and very 

 many of them were quite different in colour from that which they 

 usuallv jtresent ; still there were trusses, for instance those shown by 

 Messrs. Paul A: Son, Messrs. Perkins, of Coventry-, Mr. Cant, and the 

 Rev. E. Pochin, such as are rarely surpassed ; but even these had 

 gi'eatly deteriorated in beauty before the close of the day, notwith- 

 standing the awning employed to keep off the sun. As regards the 

 attendance of visitors, the Show was also very successful, for the gar- 

 dens, which are just now in high condition and extremely gay with 

 bedding plants, were thronged with a large and fashionable company; 

 and in the afternoon, besides other eminent personages, their Koyal 

 Highnesses the Prince and Princess Christian, the Prince and Piincess 

 Louis of Hesse, the Princess Lotuse, and other members of the Royal 

 Family were present. 



Class 1, was for seventy-two single trusses, and for nurserymen 

 only. In this Mr. Cant, of Colchester, took the tirst prize with, among 

 others, excellent examples of Fisher Holmes, Mrs. Rivers, Comtesse de 

 Chabrillant, Horace Vemet, Madame C. Crapelet, Mathurin Regnier, 

 Marie Banmann, very tine ; Anna de Diesbach, President, Yicomtesse 

 de Cazes, Senatexu- Yaisse, Queen Victoiia, Marechal Vaillant, -Jean 

 Lambert, Lord Macanlay, fine colour ; Paul Verdier, La Bonle dOr, 

 OUvier Delhomme, Rubens, Beauty of Waltham, Dr. .\ndry, Madame 

 Deneux DonvUle, Exposition de Brie, Mdlle. Bonnaire, Charles 

 Lefebvre, fine, but touched with the sun ; Marichal Niel, very fine ; 

 Alfred Colomb, Madame Bravy, Leopold Premier, Mdlle. Marie Rady, 

 Souvenir d'Elise, Niphetos, very tine ; Duchesse de Caylus, Xavier 

 OUbo, Madame Victor Verdier, Cloth of Gold, Marguerite de St. 

 Amand, and Souvenir dun Ami. 



Messrs. Paul & Son were second, pressing very closely for the fu-at 

 place, and had Exposition de Brie, very tine ; Mdlle. Marie Rady, 

 Madame Vidot, Madame Furtado, Camille Bemardin, P;-ince de 

 Portia, Felix Genero, Xavier Olibo, Mdlle, Marguerite Dombrain, 

 Alfred Colomb, Horace Vernet, Madame Victor Verdier, Pierre Net- 

 ting, Black Prince, Maurice Bemardin, Monsieur Furtado, and 

 Leopold Premier, the last very fine, Mr. Eraser, of Lea Bridge Road, 

 who was third, had, among others, Madame Bellenden Ker, a pretty 

 white; Gloire de Vitry, small but good; Andre Leroy, fine velvety 

 crimson purple, but rather open ; Jean Lambert, Dr. Andry, Senatenr 

 Vaisse, and Due de Rohan. Messrs. Francis, of Hertford, were fourth, 

 and Mr. Clarke, Streatham Place, Brixton, also exhibited in this cla8»_ 



