454 
Seltzer water . 
So far as I know, the magnetic qualities of iron or iron oie, 
have little or no practical effect in the operation of smelting. We 
know too little as yet about magnetism, to draw practical infer- 
ences. 
It seems to me of no consequence whether the argillaceous 
part of the common iron ore be hardened or not by roasting. The 
earth must be converted into glass in the furnace, or the iron will 
not be obtained. The action of the lime on the clay is the same, 
whether this latter be hard or soft. Let it be remembered, that in 
a very great degree the art of pottery, the art of glass making., 
and the art of smelting depends on this fact, viz 
Put into a crucible a round lump of pure clay: into another, a 
similar lump of pure lime or even limestone : into another a simi- 
lar lump of pure flint, silex, or quartz. Expose them for any 
length of time to a violent heat, they will continue as at first, clay, 
lime, and flint, except where the sides are in contact with the 
crucible. Pound them together, and put them in one crucible ; 
expose them to heat for the same time, and the product will be 
perfect glass. As potass will dissolve silex, it may be substituted 
ibr lime, T- C, 
SELTZER WATER. 
Philadelphia, Feb. 1814. 
Dear Sir — -In a note to your edition of Accum’s Chemistry, I 
find that you mention a contrivance of Mr. Cloud for preparing 
what is commonly called mineral, but more properly aerated wa- 
ter, or for saturating water with carbonic acid gas. It may not be 
improper to notice, for the information of your readers, that al- 
though the plan would appear very economical, and answer the 
purpose completely, yet the truth is, that with an apparatus made 
according to Mr. Cloud’s direction, (in a superior* style, which 
cost S the saturation was difficult to effect to that degree equal 
to the machine with the forcing pump. Mr. C. from his own, as 
well as from the evidence of Messrs. Patterson and Eckfeldt of 
the U. States’ mint, prepared aerated wafer with his apparatus ; 
but with the one made by Mr. Glentworth and myself, no satura- 
tion other than an impregnation could be effected. We followed 
