Mr. Ckiandi's burner may also be applied in several industries. It is
capable of rendering great services in the bleaching of silk and woolen
goods, and it may also be used for bleaching sponges, straw hats, and a
number of other objects.--_La Nature_.

* * * * *




THE DETERMINATION OF GRAPHITE IN MINERALS.

By J.B. MACKINTOSH.


In many instances the accurate determination of the amount of graphite
present in a rock has proved a rather troublesome problem. The first
thought which naturally suggests itself is to burn the graphite and weigh
the carbonic acid produced; but in the case of the sample which led me to
seek for another method, this way could not be employed, for the specimen
had been taken from the surface, and was covered and penetrated by
vegetable growths which could not be entirely removed mechanically. Add
to this the fact of the presence of iron pyrites and the probable
occurrence of carbonates in the rock, and it will be at once seen that no
reliance could be placed on the results obtained by this suggested
method.

As the problem thus resolved itself into finding a way by which all
interfering substances could be destroyed without affecting the graphite,
it at once occurred to me to try the effect of caustic potash. I melted a