302 PROCEEDINGS OF SOCIETIES. 
tion, but if any lady here wears a chignon and would wish to 
test its purity, one of our instruments shall be at her service this 
evening for that purpose. The pores of the skin, examined under 
the microscope, appear as deep cavities; in these extraneous matter 
collects, vulgarly called dirt, and if it is not removed by ablution, a 
suitable soil is soon formed for the minute fungus, which grows 
and spreads over the skin precisely in the same way as the lichen 
spreads over the trunk and limbs of the tree. 
In passing round the hall I am sure you will all be struck 
with the beautiful series of drawings exhibited here this evening 
by two of our members, Mr. Tatem and Mr. Clayton. They 
are peculiarly interesting and instructive, for it must be re- 
marked that they are not mere enlarged diagrams, but that they 
have been carefully drawn from the animals themselves as they 
appeared under the microscope by means of the camera lucida, 
so that their outline, and the number of times they are stated 
to be magnified, must be correct, whilst you will doubtless admire 
and appreciate the artistic skill which these gentlemen have 
displayed in finishing them off. 
And now, ladies and gentlemen, I have only to say that we 
all hope that you will spend an amusing and instructive evening 
in examining the objects under the instruments, which will be 
changed at frequent intervals. 
The President’s address was listened to with marked attention, 
after which the company dispersed to examine the objects and 
the beautiful collection of drawings alluded to; and after passing 
a pleasant and interesting evening, and partaking of the refresh- 
ments hospitably offered to them, departed about ten o’clock to 
their homes. 
MicroscoricaL SECTION OF THE MANCHESTER LITERARY AND 
PHILOSOPHICAL SOCIETY. 
Orpinary Meertine, 25th March, 1867. 
On the Microscopican Examination of Coat Asu or Dust 
Srom the FuvE 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 different 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 furnace, 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 car- 
