n can possibly be.

NOTEBOOKS

Notebooks should contain, beside the record of observations,
descriptive notes. All records of weights should be placed upon the
right-hand page, while that on the left is reserved for the notes,
calculations of factors, or the amount of reagents required.

The neat and systematic arrangement of the records of analyses is
of the first importance, and is an evidence of careful work and an
excellent credential. Of two notebooks in which the results may be,
in fact, of equal value as legal evidence, that one which is neatly
arranged will carry with it greater weight.

All records should be dated, and all observations should be recorded
at once in the notebook. The making of records upon loose paper is a
practice to be deprecated, as is also that of copying original entries
into a second notebook. The student should accustom himself to orderly
entries at the time of observation. Several sample pages of systematic
records are to be found in the Appendix. These are based upon
experience; but other arrangements, if clear and orderly, may prove
equally serviceable. The student is advised to follow the sample pages
until he is in a position to plan out a system of his own.

REAGENTS

The habit of carefully testing reagents, including distilled water,
cannot be too early acquired or too constantly practiced; for, in
spite of all reasonable precautionary measures, inferior chemicals
will occasionally find their way into the stock room, or errors will
be made in filling reagent bottles. The student should remember that
while there may be others who share the responsibility for the purity
of materials in the laboratory of an institution, the responsibility
will later be one which he must individually assume.

The stoppers of reagent bottles should never be laid upon the desk,
unless upon a clean watch-glass or paper. The neck and mouth of all
such bottles should be kept scrupulously clean, and care taken that no
confusion of stoppers occurs.

WASH-BOTTLES

Wash-bottles for distilled water should be made from flasks of about
750 cc. capacity and be provided with gracefully bent tubes, which
should not be too long. The jet should be connected with the tube
entering the wash-bottle by a short piece of rubber tubing in such
a way as to be flexible, and should deliver a stream about one
millimeter in diameter. The neck of the flask may be wound with cord,
or covered with wash-leather, for