Chemistry International
Vol. 23, No. 4
July 2001
Preface
from Practical Chemistry by Micro-Methods
It must be evident to many that the time has come for a change in some
of the methods of teaching practical chemistry. Classes seem to get
larger every year, and the standard is being gradually raised. Much
which was done in the first year of a university course must be pushed
into the schools curriculum. It follows that many experiments
which could once be performed by each individual must perforce be omitted,
and there is a tendency to meet the situation by adapting the practical
course rather to the convenience of the laboratory than to the individual
needs of the students. The majority who come to the chemical department
today, are applying themselves to the science as a means and not as
an end, seeing how divergent these ends are, it is a pity that the training
must so often be the same. At the best this is but a compromise.
Organic chemistry, particularly, is neglected because of the expense
of many reagents and the danger of working with large quantities of
inflammable materials. The method of practical microchemistry is that
of working with minute quantities of material, specks of solids, drops
of liquids. With this method the difficulties which would hamper many
a laboratory will be found to vanish. A student, for example, may without
danger prepare a few ccs. of the gases, however inflammable or explosive,
and he can study the properties of much solvents as school, ether, chloroform
or benzene by the use of drops without danger to himself or anxiety
to his teacher.
There is nothing which at present is done by students with large apparatus
that cannot be done with the micro-method, but there is much that can
be done with small apparatus that is sheer waste when done on the larger
scale.
With small reagent bottles and small apparatus the benches and general
equipment of the laboratory may be greatly simplified. Everything is
easier to find and to handle. A students whole outfit may be put
upon a tea-tray, and with his laboratory thus all at hand the student
may sit down to his work with consequent sparing of fatigue to himself
and to his teacher. The class room whatever the stage of the work, becomes
a place of peace and quiet, and the foul atmosphere so often the result
of work on a large scale, is avoided. This means a great gain from the
point of view of the students health, a matter which in science
teaching is often sadly neglected. The methods of micro chemistry are
exceedingly rapid, for example, by the use of the table on page 65,
one of my staff was able to identify the bases of fifteen unknown simple
salts in ten minutes with only one doubtful case. This, I think, must
be a record. Such rapid work is the result of using drops, and employing
one glass slide instead of several test tubes. Several reactions may
be viewed simultaneously, and by the aid of a pocket lens, studied with
a care which is not possible with the test-tube. One drop of a solution
divided into three parts suffices in many cases to characterise at once
an unknown base. After the reaction the slide is washed and dried in
a second and ready for the next test. With this sparing of time it follows
that much more work can be got into the working hours, and in consequence
studies which were once spread over many years may be condensed into
a few. The economy also in energy and in expense is enormous, with the
result that it is possible to cover a much broader field of study. This
book is intended for schools or for the earlier part of a university
course, and it covers the practical work required by the conjoint boards
of the Royal Colleges of physicians and surgeons.
While describing the methods of micro chemistry, it indicates also
how a practical course may be broadened to include exercise, in elementary
physical chemistry, qualitative analysis, volumetric analysis, and a
brief introduction to organic chemistry is given. Sufficient to give
the student a taste for this fascinating subjects.
I would like, in concluding to express my thanks to my colleagues,
Mr. W. M. Colles, for his valuable help. The Author wishes to thank
Messrs. Baird & Tatlock for so kindly providing the blocks for the
illustrations.
EGERTON CHARLES GREY
CAIRO, 1924
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