148 Hugh Taylor, Esq., on the Chemical Constitution 



be traced in other members of the coal formation ; thus, the muscle- 

 bind is a mixture of this silicate with carbonates of iron and lime. 

 This connection is not seen as the analysis stands, but becomes 

 apparent by comparing the fire-clay, calculated as anhydrous, and 

 the insoluble matter of the muscle- bind calculated to 100 parts. 



•cj ^ _, Insoluble matter 



100-00 100-00 



Here the sole difference appears to be that, in the fire-clay, a small 

 quantity of alumina is replaced by the isomorphous peroxide of iron, 

 and both lead to the same formula Alg Og 2Si 0^. This represents 

 both substances as anhydrous, but the fire-clay contains water in 

 combination, corresponding, as before observed, to two equivalents, and 

 it admits of no doubt that the insoluble matter of the muscle-bind, 

 as it exists in the rock, is also hydrated, although, from the presence 

 of organic matter, it is impossible to determine the amount of water 

 in an accurate manner. An attempt was however made to determine 

 the quantity of water by gently heating the substance so as to avoid 

 decomposing the organic matter; and in this way 308 per cent, of 

 water was obtained, but obviously no reliance can be placed upon 

 this as a quantitative determination, because it was impossible to 

 obtain a sufficient heat to expel the whole of the water without de- 

 stroying the organic matter, but it is sufficient to establish the fact 

 that water actually was present. 



The blue shale and inorganic matter of the bituminous shale, form 

 another pair very similar to one another, though different from the 

 fire-clay. In order to render this similarity apparent, I give the 

 results of the analyses calculated the blue shale as anhydrous, and 

 the inorganic matter of the bituminous shale in 100 parts. 



100-00 100-00 



