NOTES AND MEMORANDA. 
Sections of Coal. By J. Sxapze—The origin of coal 
has ever been a subject of great interest to the naturalist ; 
but so far as the microscope has been concerned in the inves- 
tigation, no satisfactory progress has been made until quite 
recently. 
The examination of sections of coal under low powers, 
either as transparent or opaque objects, is almost useless ; but 
sections, averaging between the two and three hundredths of 
an inch in thickness, under a quarter, or an eighth objective, 
show a structure as unmistakably as do sections of recent 
vegetable organisms. The teachings resulting from exami- 
nation of such sections have been truly and clearly brought 
before the public by Professor Huxley in a lecture at Brad- 
ford in January last, and again at Leicester in November 
last, and reported in the ‘Contemporary Review.’ The 
means of confirming these observations is in the hands of 
any one accustomed to prepare objects for the microscope, 
while the material is close to our hands at any moment. The 
method of proceeding is as follows :— 
A piece of coal being selected, a surface is at first obtained 
roughly by a file, or piece of sandstone; then a finer, by 
means of a hone, or piece of fine glass paper; then a still 
finer, by means of pumicestone, and after rubbing upon 
Arkansas stone, finally brought to the highest polish possible 
by friction upon plate glass. 
If the coal be very friable (which it sometimes is), it will 
be necessary to macerate the specimen in thin shell lac var- 
nish and dry it, before the whole process can be accomplished. 
In order to secure success, it is impossible to bestow too 
much pains in this preliminary operation. 
Having made a good surface, next cement it to a glass slip 
by marine glue; the marine glue used, requires careful selec- 
tion ; that usually sold frequently contains particles of the 
undissolved materials, which aré visible enough under the 
microscope. 
However, having obtained the right sort, cut thin slices ; 
