82 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



lands which are nearly surrounded by the sea, derive a very 

 mild climate from the vast extent of almost tepid water round 

 them. The pretty island of St. Honorat, opposite Cannes, which 

 is only a hundred acres in extent, and scarcely rises twenty feet 

 above the level of the sea, is almost free from frost on that 

 account. 



Sharp and protracted frosts are seldom experienced on the 

 Riviera except on low-lying grounds, where cold air collects and 

 lingers for some length of time. On ridges, or indeed on all 

 higher grounds or on hillsides, frost is due only to intense radia- 

 tion during clear nights, and is easily obviated by the use of light 

 screens of canvas, heather, or reeds. Glass frames are also used 

 very extensively, and each successive season adds several acres to 

 the extent of land covered with glass on the Riviera. 



Not that glass houses proper are very frequent on the grounds 

 of the florists. Some score of them are devoted to forcing the 

 climbing Roses and perpetual-flowering Pinks ; but by far the 

 commonest structures are low rows of glass frames, supported by 

 a single central rail, and sloping almost to the ground, while the 

 lower part of the sides is made tight with straw, heather, or sea- 

 weed. Bush Roses, Pinks, Mignonette, bulbous flowers, bloom 

 freely under such shelter, and the same is found sufficient, heated 

 or unheated, to produce French Beans, Tomatos, and Strawberries 

 in January and February. 



The use of artificial heat is by no means despised or neglected 

 by the gardeners and florists on the Riviera, but it is only occa- 

 sionally resorted to. Nearly all the large glass structures there 

 are provided with hot-water pipes, simply laid flat on the ground, 

 to insure the possibility of heating on an emergency ; but the 

 sun alone generally gives more heat than is required, so that the 

 main work consists in airing and ventilating the houses. 



Many are the plants cultivated on the Riviera which would 

 not be benefited by the use of artificial heat. To Anemones, 

 Polyanthus Narcissi, and Mignonette some shelter is at times 

 acceptable and helpful, but the principal requirements of such 

 plants are plenty of light, bright sunshine, and fresh air. 



Flowering trees and shrubs, of course, have to rough it out in 

 the open air. We will take them first. 



