504 EFFECTS OF FROST IN THE SAME LOCALITY. 



would be most surprisiiin^ if tlioy <litl not oxist. An observer of the weather who 

 shoiilil announce his havina: remarked the same tcm])erature in tlic centre and 

 environs of a town, on tlie north nnd south sides of a hill, in a low ]>lace and on 

 a hei.Ljht, would <rain little credence from those who understand these sul)jects. 

 (lardt'iiers are most csi)ecially those who should appreciate and ])ruvidc a^'-ainst 

 such dilferenccs. 



As an example of their effect, "SI. Martins cites the following: instances, which 

 occurred this last spring at ISlontpellier to the Sweet Bays, Olive trees, and Fig 

 trees. Of these plants some perished wliilc others escaped, and it was here that 

 the effects of aspect and shelter were most consjiicuous. In fact, had not the 

 ordinary thermometers shown that the minima of temperature greatly differed, 

 these trees — real living thermometers as sensitive as those of the ])hilosophieal 

 instrument maker — would have plainly indicated it. 



To begin with the Bay. In a low part of the Botanic Garden, wliere the tem- 

 perature was ascertained to have been -f 3'^ on the north side of a wall, and — 1^ 

 away from all shelter, the Bays almost all died. But it was different in a part of 

 the garden called the Bosquet de Narcisse, where a swell of the ground raised the 

 surface about six yards; here the Bays suffered little; a few were scorched, but 

 the foliage of most of them remained green. At this place the thermometer did 

 not fall lower than + 6^^. Undoubtedly, in the Bosquet de Narcisse the Bays 

 were sheltered by high Cypresses and great Celtises ; but in a neighboring garden 

 they suffered very little, although not at all sheltered. Moreover, in the low part 

 of the garden the Bays died, although they were sheltered. In short, they esca})ed 

 wherever there was any rise of the ground. Ilence it appears that the dilference 

 of a few yards in the level affects temperature so much as to produce entirely 

 different effects upon vegetation. M. Martins remarked, however, that Bays 

 stronger than the rest escaped the frost in the midst of others that died. 



It was the same with the Olive trees. In low places where the thermometer 

 fell to — 1^ they perished down to the old limbs. In a ])lace protected from the 

 north by a house they only lost their leaves. In all the district between Mont- 

 pellicr and Nismes the Olive trees of the plain suffered more or less, and had to 

 be cut back, while those on the low hills sustained no injury. None of these 

 hills are above sixty yards high, and many much lower. There was a pair of 

 young Olive trees (0/ive/tes) ])lanted near each other, but with a difference of 

 elevation between them of ten yards only ; in one the leaves were all scorched, in 

 the other they were scarcely hurt. Many cases of the same kind were observed 

 in other places. These facts ai)pear to establish a general law that " cold is most 

 injurious in low places where radiation is most intense in consequence of the tran- 

 quillity of the air, and least injurious in exposed places where the agitation of the 

 air opposes the effects of radiation." 



Fig trees and Pomegranates j)resented the same general results. 



Hence M. Martins infers that one of the first duties of a gardener is to make 

 himself acquainted with local climates, the differences among which are far 

 greater than is generally imagined. For example, there occur in the Botanical 

 Garden of Montpellier no fewer than four local climates. 1. 77ie coldest in winter 

 and hottest in summer; this is the lowest place unsheltered to the north and west, 

 and only protected to the east by some tall trees. 2. A space to the north of 

 this, protected by houses and walls; it is not so cold, hut as hot as the jirst. 3. 

 The 13utanical arrangement, sheltered on the north by an Orangery and green- 

 house, surrounded by trees and buildings, and overlooked on the south-west by 

 the hill du Peyron ; this is not so cold in winter, hut excessively hot in summer 

 le Bosquet de Narcisse and other elevated places; here the climate is more 



