se.

In this definition the weights and volumes are to be considered as
absolute, all weighings being referred to a vacuum.

The definition should properly be supplemented with a statement of the
equivalent circular rotation in degrees, minutes, and seconds that
would be produced by the standard solution of sugar used to read 100 deg.
on the scale. This constant is now a matter of investigation, and it
is thought best not to give any of the hitherto accepted values. When
this is established, it is recommended that it be incorporated in a
revision of the regulations of the internal revenue relative to sugar,
in order to make still more definite and exact the official definition
of the Ventzke scale.

The instruments should be adjusted by means of control quartz plates,
three different plates being used for complete adjustment, one reading
approximately 100 deg. on the scale, one 90 deg., and one 80 deg..

These control quartz plates should have their exact values ascertained
in terms of the Ventzke scale by the office of weights and measures by
comparison with the standard quartz plates in possession of that
office, in strict accordance with the foregoing definition, and should
also be accompanied by tables giving their values for temperatures
from 10 deg. to 35 deg..

_(b.) Weights._--The weights used should be of solid brass, and should
be standardized by the office of weights and measures.

_(c.) Flask._--The flasks used should be of such a capacity as to
contain at 17.5 deg. C. 100.06 cubic centimeters, when filled in such a
manner that the lowest point of the meniscus of the surface of the
liquid just touches the graduation mark. The flasks will be
standardized to contain this volume in order that the results shall
conform to the scale recommended for adoption without numerical
reduction of the weighings to vacuo. They should be calibrated by the
office of weights and measures.

_(d.) Tubes._--The tubes used should be of brass or glass, 200 and 100
millimeters in length, and should be measured by the office of weights
and measures.

_(e.) Balances._--The balances used should be sensitive to at least
one milligramme.

II.--SKILLED OBSERVERS.

The commission recommends that the work of polarizing sugars be placed
in the hands of chemists, or at least of persons who are familiar with
the use of the polariscope and have some knowledge of the theory of
its construction and of chemical manipulations. To thi