burn a little too fast. The cotton is rubbed between two pieces of cloth
until it burns just freely enough; then four cotton strands are taken,
twisted together, and cut into lengths of 3/4 inch and thoroughly dried.
Open out the fuse at the lower end when placing it in the mixture so as
to expose as much surface as possible in order to get a quick start, but
carefully avoid pressing the material, and use a wire to fill up close
to the fuse. A slow start often spoils the experiment, through the upper
end of the cylinder becoming nearly filled up with potassic chloride,
etc.

By paying attention to such details, and following the method
recommended, the apparatus yields very satisfactory results with
bituminous and semi-bituminous coals.--_Chemical News_.

* * * * *




EXPLOSION AS AN UNKNOWN FIRE HAZARD.


Words pass along with meanings which are simple conventionalities,
marking current opinions, knowledge, fancies, and misjudgments. They
attain to new accretions of import as knowledge advances or opinions
change, and they are applied now to one set of ideas, now to another.
Hence there is nothing truer than the saying, "definitions are never
complete." The term explosion in its original introduction denoted
the making of a _noise_; it grew to comprehend the idea of _force_
accompanied with violent outburst; it is advancing to a stage in which