March 6, 1885. 



SCIENCE. 



195 



blowing down the houses, whose walls were 

 already weakened by the earthquake. 



The geological characteristics of the coun- 

 try are described in the next article : it will 

 therefore suffice here to say that the seismic 

 phenomena seem to be intimately related to 

 the geological growth of the mountain system, 

 especiall} 7 the Sierra Nevada, the elevation of 

 which is apparently not yet completed. A 

 commission, consisting of three mining engi- 

 neers, under the presidency of Sr. D. Manuel 

 Fernandez de Castro, has been appointed by 

 the Spanish government to study this series of 

 earthquakes, and has already distributed a list 

 of thirt3 T -three interrogatories relating not only 

 to the time, direction, and other particulars of 

 the earthquake shocks, but also to various 

 atmospheric phenomena, such as the pressure, 

 temperature, clouds, etc. 



C. G. Rockwood, Jun. 



THE SIERRA NEVADA OF SPAIN: THE 

 SCENE OF THE RECENT EARTH- 

 QUAKES. 



The Sierra Nevada of Spain, though full of 

 interest for the tourist, the man of science, or 

 the student of history, has been little visited, 

 and almost nothing has been written about it. 



This sierra forms a compact body, twenty- 

 five miles wide and fifiyy miles long, completely 

 isolated, and without directly connected lateral 

 spurs or terminal ridges. Surrounded by an 

 alluvial plain as it is, it has, nevertheless, 

 certain smaller neighbors which seem, like 

 itself, to have been ejected from below. Its 

 crest has been denuded by the elements, and 

 its sides scored by brooks or torrents which 

 diverge in all directions from the central axis, 

 feci by the rains of spring and the melting 

 snows of summer. Four principal streams, 

 descending to the north-west, meet at the very 

 foot of the Alhambra, and unite their waters 

 before traversing the renowned plain of La 

 Vega. Their cascades and ripples, descending 

 from the mountain crest above, give to the 

 adjoining valley a delicious freshness during the 

 torrid months of summer. To these waters 

 is due the immense isle of verdure presented 

 by the Vega at a time when nearly all southern 

 Europe is scorched dry by the sun. At many 

 points the rivers run in narrow, deep channels 

 easily dammed. From their sources to the 

 moment when they reach the plain, their aver- 

 age descent is one to ten, almost the maxi- 

 mum for running waters. At that point they 

 are captured : not a drop escapes. All the 



irrigating works and canals, the customs gov- 

 erning the distribution of water, even the 

 rules recalled by the strokes of the bell 

 nightly from the minarets of the Alhambra, 

 are the legacy of the Arabian civilization 

 which blossomed on the plain before it was 

 driven to a last refuge on the mountain. 



On the north, three rivers descend to the 

 plain of Guadiz ; but, their sources not being 

 fed by perpetual snows, when the rainy season 

 has passed they dry away. In consequence 

 this plain is as sterile, bare, and forbidding 

 as that of the Vega is green and inviting. 

 Wherever the eye wanders, apart from the 

 sierras, lies a reddish-gray plateau of dusty 

 alluvium, seamed and rent by precipitous 

 canons. Nothing recalls the idea of life : the 

 desolation is as that of an unknown country, 

 grand and terrible. All the valleys and plains 

 of this part of Andalusia present the same 

 impressive and melancholy features. Gustave 

 Dore, who passed through this region many 

 years ago, has profited by his experience to 

 introduce memories of it in some of the most 

 strange and fantastic productions of his pencil. 

 This sterile region is poor, unpeopled, almost 

 unknown, and practically cut off from com- 

 munication with the rest of Spain. 



Farther to the west is the country of the 

 Alpujarras, so celebrated in Moorish history 

 for the terrible conflicts of which it was the 

 theatre. More than one poet has celebrated 

 the combats of the Christian and the Moor 

 in the narrow defiles and rocky gorges of the 

 sierra ; but all these imaginary descriptions 

 fall far short of depicting the scene as it ap- 

 pears in realit3 T . 



The Alpujarras are composed of two cistern- 

 like basins, absolutely closed to the outer world, 

 except by two narrow gorges cut in the rock 

 by the rivers which traverse them. The first 

 of these rivers, the Rio Grande de Ujijar r 

 descends directly from the heights of the 

 Sierra Nevada, passes by the site of that town, 

 and, with its affluents, waters the basin of 

 Ujijar, the ancient capital of the little Moorish 

 kingdom. It issues by a deep caiion, and falls 

 into the Mediterranean by the little port of 

 Adra at no great distance. The second, the 

 Guadalfeo, runs between the Sierra Nevada 

 and Contraviesa, close by the former, whose 

 slopes it drains. Emerging from the basin, it 

 turns abruptly to the south, reaching the sea 

 near Motril. Just' before entering the gorges 

 of the Sierra Contraviesa, the Guadalfeo re- 

 ceives the brook of Beznar from a point 

 elevated above the plain of La Vega, whence 

 Boabdil, the last of the Moors, is said to have 



