alt appears to be formed when a
solution of the carbonate of soda is heated with carbonate of ammonia,
and probably also when a solution of the bicarbonate is heated. Its
taste is less alkaline than that of the carbonate, into which it is
converted when strongly heated by losing one-third of its carbonic
acid.'

That it was one of the products of soda cannot reasonably be doubted.
Biborate of soda (with which I have been experimenting lately) has
certainly wonderfully preservative powers, especially in conjunction
with common salt, or saltpetre; but then it has not the caustic
properties of natron. May not natron have been a fixed alkali, or has
the native carbonate of soda more caustic and antiseptic properties
than the usual carbonate of soda of commerce, which plainly cannot be
intended?

We have here a most interesting subject to solve as to the component
parts of the ancient natron; my suspicion is that natron, as used by
the Egyptians, was a mixture of biborate of soda, caustic soda, and
muriate of soda. [Footnote: The following report appeared in the
California Alta, 24th June. 1874:

"AN INTERESTING DISCOVERY.--Several weeks ago we mentioned the
departure of Mr. Arthur Robottom, Birmingham, England, on a search for
borax in the southern part of California. He has now returned,
bringing news of an interesting and valuable discovery. Beyond the
Sierra Nevada, in the Enclosed Basin of North America, about 140 miles
in a north-eastward direction from Bakersfield, there is the bed of a
dry lake filled over an area of fifteen miles long by six wide with
saline crystals to a depth of about six or eight feet. The appearance
of the surrounding country clearly indicates that water once stood
sixty feet deep here over a large area, the ancient beach being
distinctly traceable. The most remarkable fact about this-saline
deposit is that in its middle there is a tract, five miles long and
two wide, of common salt, while on the outside there is a deposit of
borate of soda, three feet thick, and under this a lower stratum
composed of sulphate of soda and tincal mixed together, from one to
three feet thick. These minerals are all in crystals, the sulphate of
soda and tincal forming a solid mass, almost like stone in its
hardness. The borate of soda is of a dirty hue, but the salt, which
lies above the level of the entire deposit, in some places to a depth
of seven feet, is white as snow. The report of natural deposits thus