52 On the Terrestrial Arrangements connected with 



of the Rhine rose formerly to a much higher level than at 

 present. At that period, the river deposited a species of 

 earth of a yellowish- white colour, which bears the name of 

 marl (in German, Loss). This earth may be seen to the right- 

 of the public road between Remagen and Sinzig, extending in 

 compact masses high on the neighbouring hills. It occurs, 

 moreover, on the road from Poppelsdorf to Typendorf. It is 

 likewise a gift of Switzerland ; though many tributaries of the 

 Rhine, rising in the Schwarzwald, Overwald, &;c., come in for 

 a certain share. The vegetation between Remagen and Sin- 

 zig proves it to be a mould possessing strong productive 

 powers, though inferior to that of the Faulhorn and other 

 mountains of Switzerland. 



II. Saltpetre. 



Chemical experiments have demonstrated, beyond all doubt, 

 that saltpetre, a well-known salt, requires for its production 

 the presence of animal remains. From time immemorial 

 this salt has been procured from Egypt, the East Indies, &c. ; 

 formerly in smaller quantities, but since the invention of gun- 

 powder, of which it is the chief element, its importation has 

 become very considerable. In those hot countries, the salt 

 effloresces on the surface of the ground. The species of 

 rock from which it is secreted, has recently been examined 

 in the island of Ceylon, where saltpetre is of frequent occur- 

 rence, and the result has shewn it to be a limestone con- 

 taining animal matter. Mariano de Rivero discovered, not 

 many years ago, immense quantities of a similar salt, the 

 so-called cubic saltpetre^ in the wilds of Atacama, a pro- 

 vince belonging to Peru. The bed which it forms is over- 

 topped by a thin coating of earth, and extends in one direc- 

 tion for upwards of an hundred miles, in beds of variable 

 thickness. There is not the least doubt that a multitude of 

 animals found their grave in this quarter. 



How singular, that one race of animals was doomed to 

 perish, in order to furnish, in such vast quantities, the mate- 

 rials for the destruction of other races of animals ; and we 

 grieve to think even for the slaughter of human beings when 

 engaged in deadly warfare. But whatever may be the per- 



