172 INORGANIC CONSTITUENTS OF THE 
the stony nuclei and silicified shells of polythalamie,' and if 
this is correct the organic origin of the clay would only be ante- 
dated. All published analyses of clays being made, like those of 
the coal ashes, for other purposes take no notice of the solubility 
of the various constituents, but it seems probable that an exami- 
nation in this direction might throw some light on the subject, 
and I hope shortly to take the matter up. 
The presence of phosphoric oxide in coal ashes is not noticed in 
many published analyses, but as this substance might easily be 
overlooked and determined along with, and as alumina or iron, 
according to the method of analysis employed, its not being in 
list of constituents does not necessarily imply its absence, unless 
it is noted as having been looked for. Le Chatelier and Leon 
Durand-Claye® have given analyses of French coal ashes, showing 
from 0-2 to 1-5 per cent., and E. Riley® has found in Welsh coals 
m 0-21 per cent. to 3 per cent. of phosphoric oxide in the ash. 
seems unlikely that it could be removed from either source by 
solution and be deposited in the coal. It may be observed, im 
matter present, and that in the floor from the galley way the ae 
that the phosphorus compounds offer very considerable resis ae 
to removal by solution under circumstances which  cagaalll 
analagous to those under which the coal seams were 
deposited. 
ee ei 
1 Jahresb. f. Chem. 1854, p. 885. 
? Bulletin de la Soc. d’Encourag. I’Industrie Nationale, 1873. 
* Percy’s Metallurgy Fuel, p. 352. + itl 
* Knapps’ Technology, by Ronalds and Richardson, vol. 1, P “" 
