470 Scientific Intelligence. [Juna, 
ment. If the stones were laid alternately with the narrow and 
broad ends downwards, 1 am of opinion that a greater regularity 
would be preserved; for by drawing a line, as represented, down 
the intersertion between, it will be seen that as one of the stones is 
forced downwards, the adjoining ones are liberated in a propor- 
tionate degree. 
It certainly would be a more effectual way to let the stones, if 
hewn in a wedgelike form, alternate with one another thus— 
In this case a weight upon the centre stone would press equally 
upon the two adjoining ones ; and a weight upon the stones having 
their broad ends downward would not be so liable to force them in 
as what it would upon a stone narrowed downwards. 
I conceive, however, that as the stones are shaped for the pur- 
pose of paving, a different arrangement might be made of them, 
more conducive to strength and durability ; for instance, an alter- 
nation of stones in the following shape, 
laid together, would rest upon one another through the whole line. 
and, like an arch, would receive much strength and security by 
resting upon a strong curb or butment. : 
Should these observations be thought worthy of a place in your 
Annals for the next month, it will much oblige, 
Dear Sir, yours very truly, 
6, Adam-street, April 25, 1816. . H. H. Hormes. 
VI. On the Ore of Copper described and analysed in the Annals of 
Philosophy, vol. vit. p. 321. 
(To Dr. Thomson.) 
SIR, 
From your late publication, I perceive you give us your own 
recent analysis of what you consider as a new ore of copper, in 
which you have considered the whole of the copper in a state of 
peroxide as combined with carbonic acid, and that the silex is a 
stranger to the constitution of the mineral. 
I shall just remind you of the passage in the late tract of Berze- 
lius, published by yourself, p. 35, and of the analysis of Lowitz 
published by Lucas, part 2d, p. 353, that afford reasonable ground 
for not rejecting the silex as a constituent in the mineral dioptase, 
which your new ore much resembles in its external characters. 
