143 
Ordinary Meeting, April 2nd, 1867. 
Edward Schunck, Ph,D., F.R.S., &c„ President, in the 
Chair. 
Sir Henry Holland, Bart., M.D., F.RS., &c., was elected 
an Honorary Member of the Society. 
Messrs. G. C. Lowe and W. L. Dickinson were appointed 
Auditors of the Treasurer’s accounts. 
“ On the Microscopical Examination of Coal Ash or Dust 
from the Flue of a Furnace, illustrated by the Microscope,” 
by J. B. Dancer, F.R.A.S. 
When coal is burnt in a furnace to which atmospheric air 
has free access, a portion is converted into gaseous and 
volatile matter; and the incombustible substance which 
remains is the ash. The amount of ash in coals from differ- 
ent localities is very variable; it is said to range from 1 to 
35 per cent. The ash or dust which is the subject of this 
paper was collected from the flue of my steam boiler fur- 
nace, in which common engine coal is used as fuel. This 
coal leaves a considerable amount of incombustible matter. 
A specimen of the dust is now before you ; it is of a reddish 
brown colour, and free from soot or carbonaceous particles.* 
When this dust is examined under the microscope with 
a power of 40 or 50 diameters, it is found to consist of 
ferruginous matter and crystallised substances, some par- 
* Mv attention was drawn to this subject by Mr. Johnson, of Wigan, in 
Noyember, 1866. 
Proceedings — Lit. & Phil. Society. — Yol. YL— No. X4— Session 1866-7, 
