396 AMAZONIA AND LA PLATA. 



the north-west coast of North America. " The general conchision, which seems 

 to be fully established, is that the southern hemisphere is not colder than the 

 northern, and that all arguments based upon an opposite assumption must be set 

 aside. I think that this belief, as well as many others regarding physical 

 geography, originated in the fact that physical science, in its mere exact form, 

 had its birth in Western Europe, a region which, especially as to climate, is 

 altogether exceptional in its character. The further our knowledge, yet too 

 limited, has extended in the southern hemisphere, the less ground we find for a 

 belief in the supposed inferiority of its mean temperature. AVhat we do find, in 

 exact conformity with obvious physical principles, is that in the hemisphere 

 where the water surface largely predominates over that of the land, the tempera- 

 ture is much more uniform than where the land occupies the larger portion of 

 the surface. In the former the heat of summer is mainly expended in the work 

 of converting water into vapour, ond partially restored in winter in the conversion 

 of vapour into water or ice." * 



Flora of Argentina. 



Tropical woodlands analogous to those of the Brazilian sel va and certain parts 

 of Paraguay occur only in the provinces of Sal ta, Jujuy, and Tucuman at the foot 

 of the Plateau border ranges, and in Chaco along the banks of the Pilcomayo and 

 Bermejo. Round its margin this forest region passes by gradual transitions to the 

 natural parklands, where the woods intermingled with the prairies constitute the 

 fairest and most fertile districts of Argentina. All the forest species are represented 

 in these scattered woods and thickets, which occupy considerable tracts in the 

 northern provinces. But the more valuable timber, cabinet and dyewoods, are 

 already disappearing in the neighbourhood of the large towns. 



From the lack of moisture and vegetable humus, and from the presence of 

 saline elements in the soil, the vegetation acquires a peculiar character. In such a 

 climate those trees alone can flourish which bear slender leaves, spikes, or thorns, 

 diffusing little shade. On the slopes bordering Catamarca and Santiago del Estero 

 are met the cahil, a species of acacia useful for tanning purposes, and the quebracho 

 Colorado {loxopterijgiuin Lorcntzii), also rich in tannin, and owing to its strength 

 and elasticity much valued for railway sleepers. 



On the dunes, and generally in the sandy districts, the most com mon tree is the 

 algarrobo (prosopis), while regiments of the woody cactus and more ramifying 

 Barbary fig are characteristic of a very dry soil. In Chaco most of the space is 

 occupied by palm groves composed mainly of the copernicia ccrifera. Farther south 

 they diminish in extent, breaking into small thickets or clumps chiefly consisting 

 of the trith'mnx campedrk. The yatai [coco^ yatai) occurs more especially in the 

 provinces of Corrientes and Entre-Rios between the Parana and Uruguay rivers, 

 which region contains four of the ten or twelve palms peculiar to the Argentine 

 flora. In some districts thorny trees, such as the gleciituchia aiiwrpZ/oidcs, develop 



* JVotes of a Xatitrallst in South America, pp. 272 — 's. 



