176 On the Manna of the Scriptures. 



dence that the primitive stratification is not obliterated, as 

 Mr Forbes has maintained, but that it is preserved through 

 the whole mass of the glacier. They shew also, better than 

 any discussion, how little analogy there is between the struc- 

 ture of the glacier and that of a lava stream. 



Barton, 30f/t Mcvj. 



Postscript. — Concerning the motion of the glacier during 

 winter, you will see that the results of Mr Forbes, as stated 

 in his 14th letter, agree, in a very satisfactory manner, with 

 those obtained by M. Agassiz and myself on the glacier of 

 the Aar. In this respect, as in many others, the Glacier of 

 the Aar is not at all an exceptional one, but is governed by 

 the same laws as those of Chamouni, and all large glaciers in 

 general. 



On the Manna of the Scriptures. 



Dr Wright* describes a substance he met with, under the name of 

 manna. We found, says he, " in one part of the mountains (probably 

 on the return route) great quantities of a sweet substance found on the 

 leaves of certain trees, generally the oak and gall-nut tree, and 

 which is called gezza in Koordish, and'wanna in Syriac, and perhaps 

 honey-dew in English. It forms on the leaves in such abundance, 

 that, when they are dried and pounded, it comes off in scales, and 

 is collected and used as an article of food. When melted and strained, 

 in order to separate the crumbled leaves, it is very delicious, and is 

 eaten by the people often in preference to honey. In the summer 

 it is collected in large quantities, and put up for winter use. Often, 

 as we were riding along among the trees loaded with it, we found it 

 pleasant to break off the branches and lick the leaves, which were 

 so coated with it, that in a very few minutes our appetites were sa- 

 tisfied. There is a species of willow growing in the water-courses in 

 Persia, on which this article is sometimes found ; but we have never 

 seen it there in such abundance as in the Koordish mountains." 



The term manna ordinarily refers to the well-known product of 

 several species of Fraxinus, *' that grow spontaneously in Italy and 

 Sicily, and very probably in all the oriental Mediterranean region," 

 and which is used for medicinal purposes. Substances which re- 

 semble this in form, or taste, or mode of production, are also called 

 by the same term, which in every case, therefore, needs defining. 

 The gezza was observed in June, and, from Dr Wright's account, we 

 infer it was a semifiuid exudation upon the leaves of certain trees. 



* Dr Wright is a member of the American Mission, at Oroomiah, in Persia. 



