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tides transparent, others white and red. It contains also 
a number of curious looking objects, which vary consi- 
derably in size and colour; the majority of these bodies 
are spherical, and when separated from the irregularly 
shaped particles forming the bulk of the dust they become 
interesting objects for the microscope. I shall confine my 
remarks more especially to these globular bodies. Some of 
these are as perfect in form as the most carefully turned 
billiard balls, and have a brilliant polish. The various 
colours which these globules exhibit give additional interest 
to their examination. Some are transparent crystal spheres, 
others are opaque white, many are yellow and brown, and 
variegated like polished agates or carnelian of different 
shades. The most abundant of the highly polished balls are 
black ; there are others which look like rusty cannon balls — 
some of these have an aperture in them like a bomb shell, and 
many are perforated in all directions. To obtain these 
objects the dust should be washed in a bowl and all the 
lightest particles allowed to float away ; the remainder con- 
sists of fragmentary crystalline and ferruginous substances ; 
mixed with these are the polished balls described, which 
under the microscope, by a brilliant reflected light, look like 
little gems. To separate the spherical bodies from the irre- 
gular ones it is only necessary to sprinkle some of this 
material on an inclined glass plate, and by gentle vibration 
the balls roll down, and can thus be collected. Having satis- 
fied ourselves with the examination under the microscope, 
it is natural that we should desire to know more about 
these novel objects. What is their elementary constitution ? 
Why are they spherical ? How do they get into the flue ? 
I have not attempted a chemical analysis of these minute 
bodies, many of which are less than the 100th part of an 
inch in diameter. I can only therefore offer an opinion as 
to their probable constitution, judging from what is known 
of the chemical analysis of coal ash, and from the appearance 
