NOTES AND QUERIES. 
349 
1 elements has been effected between the chloride of sodium and the car- 
^ bonate of lime, giving rise to the formation of chloride of calcium and car- 
e bonate of soda. It has been long suspected that the natural production of 
I carbonate of soda was dependent on the presence of carbonate of lime, and 
!, was brought about somewhat in this way; but what the conditions are under 
which the separation of the carbonate of soda from the chloride of calcium 
1 is effected, without allowing the former to exert its ordinary converse 
action upon the lime-salt and reproducing carbonate of lime, is a question 
1 that would form a very interesting subject of scientific inquiry. This 
e is, I believe, the first time that the natural production of alkali from sea- 
, water itself, without organic agency, has been observed. 
It is hardly probable that the production of carbonate of soda in this 
e way is bmited to a few miles' distance from Aden. As the shore is so 
f very similar along the whole 1125 miles which form the south-east coast of 
Arabia, there is a reasonable expectation of finding it at many places else- 
1 where; and an article so much in request, so easily procured, and with 
: water-carriage close at hand, might yield a fair amount of profit to an en- 
t terprising shipper who should collect or purchase it upon the spot. 
; Lake Supekior Silver. — The silver found at Lake Superior is native, 
• and is the most extraordinary metallurgical paradox yet discovered, in 
? which nature has shown that she can completely surpass art. It is found 
1 in large quantities in the native copper mines of that district. The com- 
1 binatious of the silver with the copper present most varied forms ; in some 
instances the native silver is found running through a mass of native cop- 
per in veins of varied thickness, like veins in marble ; at other times it is 
found attached to masses of copper, in many beautiful floriated forms of a 
large size and sometimes resembling the stumps of old trees, and fre- 
quently covering the whole surface of a mass of copper on all its sides to 
a considerable thickness, and presenting most beautiful forms in cubes, 
prisms, and four-sided pyramids, which appear as though the whole mass 
of copper had been thickly electrotyped with the precious metal. Its 
varied forms and its extreme purity, although in conjunction with the 
• copper, renders it a subject of the greatest curiosity, both metals having 
been, some think, subjected to a heat that must have been equal to a re- 
finer's sinelting-heat, and yet the metals are each found in perfect purity. 
In all the mass of copper of this vast district, silver is associated with it 
to a greater or less degree, but not in suHicient quantity to pay for its se- 
paration. The rock in which the silver of this district most abounds is an 
amygdaloidal trap of a very compact nature. The miners of this district 
for many years considered the native silver as a perquisite,— as they used 
to say they were employed to mine for copper and not for silver ; there- 
fore the proprietors rarely used to get the silver, but the miners always 
had an abundance. This state of things now no longer exists, and the 
proprietors get a large share of this valuable production. 
In a contribution to the 'Washoe Times,' Mr. J. 13. Truckee states that 
he had the most valuable collection from the Superior mines in Europe, 
which he was solicited by the commissioners for mines and minerals to 
place in the Paris Exhibition as an illustration of the productions of the 
mines of Lake Superior, they undertaking to return the collection intact 
when the Exhibition closed ; but at the time when he looked for its return, 
he was waited upon by two gentlemen, who came from the Emperor of 
France, to request that the collection might remain at the School of Mines 
in Paris. As Mr. Truckee considered this school the first of its class, 
he consented to his collection remaining there. 
In this collection there are crystals of pure native copper in clusters of 
perfect cubes, to which are attached floriated native silver. 
