Dr Daubeny on the Columnar Structure of Trap-Rochs. 69 
immediate contact with the falling rivulet, it exhibits some well- 
washed columns. 
It seems clear, then, that in this instance at least, the con- 
tinued action of water had developed the natural structure of 
the rock ; for, if these columnar concretions existed there ori- 
ginally, why are they limited to that portion of the rock which 
has been washed by the torrent ; or if they depend merely on a 
peculiar condition of its component parts, how comes it, that the 
basalt should have all at once undergone such an alteration, as 
caused it to lose its regularity of form, and that at the very 
point at which it ceased to be affected by the action of water ? 
There seems, therefore, little ground for doubting that the 
columnar form of the basalt has, in the present instance, been 
developed in the manner above mentioned ; and the same expla- 
nation will, I conceive, apply to the lava of the Vivarais descri- 
bed in a former part of this paper, and perhaps to certain basalts 
exhibiting the same structure. To what extent, however, this 
hypothesis is to be received, or how far it may be regarded a^ 
accounting in general for the manner in which the internal 
structure of these rocks has been developed, is a question which 
I freely leave open for others to decide upon, satisfied with 
having shewn that the views in which I have indulged, are, to 
a certain length at least, not wholly hypothetical. 
Magd, Coll. Oxford, \ 
April 182% J 
Art. Analysis of Tutenag, ' or the White Copper of 
China, By Andrew Fyfe, M. D. Lecturer on Chemistry, 
Edinburghr 
"V" ER Y different statements have been given of the composition 
and origin of Tutenag, used by the Chinese in the formation 
of many of their metallic utensils. 
According to Keir, it is a white alloy of copper, zinc, and 
iron, which is very hard and tough, but at the same time mal- 
leable, and taking on a fine polish. An inferior sort of it, ac- 
cording to the same author, is more of the colour of brass. 
