370 
ADDITIONAL NOTICES. 
[June 14, 1858- 
in Europe, in the Jura, as afforded by the river Doubs ; in France, by the 
Saone and Loire ; in the Alps of Trent and Belluno, by the Adige, Piave, and 
Tagliamento ; in the Julian Alps, by the Isonzo, Sau, and Knlpa ; in Dal- 
matia, by the Unna, Verbitza, and Narenta ; in the Apennines, by the Tiber, 
Velino, and Pescara ; in the north of Bohemia, by the Elbe ; in North America, 
by the Missouri and Rio Grande ; in India, in the Salt Range, by the Indus ; 
east of the Aravalli mountains (Rajpootana), by the Bairass and Chumbul ; 
in the Nizam’s dominion, by the Wurda and Godavery, &c. A band, or 
circumvallation of the (calcareous) formations denoted, extends on the north 
and west of the Alps from Wiener-Neustadt to Nice. The primary direction 
of the principal rivers of the southern and central Alps is remarkable in so far 
as the upper courses of the Enns, Salza, Inn, Rhine, Reuss, and Aar, extend 
nearly parallel to the southern crest of this circumvallation — that is, from 
south-west to north-east. All these rivers suffer an inflection towards the 
north, in entering this bend, to pursue a new deviation on emerging from it, 
so that the water-courses of the Southern Alps have a north- east, and those of 
the Central Alps a north-west, direction. The analogy is borne out in the 
western part of the Alpine region by the rivers Arve, Rhone, Isere, and 
Durance. The mean fall of the chief Alpine rivers may be taken as follows : — 
In the Southern Alps. 
Upper course of the Enns, 14 ft. per Eng. m. — across the calcareous band, 27 ft. 
„ Salza, 32 „ ,, 33 ft. 
„ Inn, 42 „ ,, lift. 
In the Central Alps. 
Rhine, 108 „ „ 15 ft. 
Reuss, 280 „ „ 0*5 ft. 
Aar, 324 „ „ 8 ft. 
These figures show that the more rapidly inclined is the upper bed of a river 
the less is its descent when crossing cretaceous and the upper Jura formations. 
These rocks then offer a great resistance to the passage of water — a pheno- 
menon not met with in Madeira. 
In offering to the Royal Geographical Society of London the Physical Map 
of the Island of Madeira, with these Explanations, I must add the following 
remarks. 
In drawing up the Map, I enlarged upon the scale of the marine chart of 
Capt. Yidal, r.n. (1843) ; and for the elevations I consulted what that officer 
has published on the Geography of Madeira, as well as the results of the 
observations of Sir Charles Lyell and Mr. G. Hartung. I owe many obliga- 
tions to the constant kindness of Mr. Hartung, who has readily communicated 
to me from his well-stored portfolios that with which a residence of six 
winters in Madeira made him acquainted. I should not have ventured to 
publish the Map without the assistance of a friend like himself, who knows 
the island perhaps better than any other geographer. At the same time that 
I acknowledge the thanks due to Mr. Hartung, who has favoured me with 
his advice also during the engraving of the Map, I must also record those to 
another friend, who knew Madeira from repeated visits — I mean Dr. F. 
Mittermaier, the brother of the author of * Madeira als Heilungsort.’ 
As to my own remarks, they have been nearly limited to considering the 
characteristic formation of the island, and the distribution of the plants most 
distinctive of its vegetation. During my travels I made some thermometrical 
observations, which, however, merit little consideration, since they did not 
