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Remarks on Iron 0res y the mode of working them , afid 
general classification . 
The following remarks are from Mr* Mushet, 3 Phil* 
Mag. 193. 
Ir on-stones, though commonly denominated ores of 
clay, contain notwithstanding a variety of mixtures, and 
may with propriety be divided into the following classes : 
1. Iron-stone that has clay for its chief componant earth* 
and this clay comparatively pure and free from sand. 
2. Iron-stone possessing lime for its chief mixture, and 
this lime also comparatively destitute of sand* 
3. Iron-stone that unites clay and Erne, containing large 
proportions ofsikx 5 hence, for distinction’s sake, these may 
be denominated siliceous iron-stones. I shall therefore* 
In naming these varieties, use the following terms as they 
are arranged in succession. Argillaceous, calcareous, and 
siliceous iron-stones. None of these earths exist singly 
with the iron. All iron-stones contain a mixture of the 
three, in various proportions ; from which arise the 
supposed variety of the qualities of crude iron, which 
each respective stone is said to contain. There are some, 
however, which are composed of nearly the same propor- 
tions of clay, lime, and silex ; and these commonly afford, 
when compared with themselves, a similar quality of crude 
Iron. 
Nature, in the formation of these secondary ores of 
Iron, has invariably impressed characters upon them, ea- 
sily to be developed : by which means their qualities, 
and the consequent effects produced in the blast-furnace, 
may be accurately and distinctly prejudged. The source 
of this information is, the study of the nature of the uni- 
ted earths ; by ascertaining the quantity and proportion of 
which, we are enabled to pronounce exactly upon the 
quality of the iron likely to be obtained from the ore. 
We must not, however^ consider these characteristic fea- 
