es the number of centigrammes
and milligrammes that must be added to the weights already placed upon
the pan of the balance in order to obtain an equilibrium, to about a
half division of the lower dial.

The value of each division of this dial varies from 3 to 10 milligrammes
according as the balance shows 0.1 or 0.5 milligramme. As the dial has
10 divisions on each side of the central mark, we thus estimate, without
tentatives, the three last centigrammes or the last decigramme,
according to the sensitiveness.

At this moment the doors of the cage are closed, in order to prevent
draughts of air, the gas is turned on by means of a regulating cock, and
the balance is manipulated by first lowering the beam and then bringing
the pans to a standstill. We then read the difference of the divisions
traversed to the left and right upon the luminous dial through the image
of the reticule. The images are reversed upon the dial, but practice
soon causes this petty difficulty to disappear. This number of divisions
indicates the number of milligrammes and fractions of a milligramme by
which it is necessary to shift the counterpoise on its arm in order to
obtain a perfect equilibrium, which latter is verified by a simple
reading. Every half division of the dial corresponds, as to weight, to
the sensitiveness indicated for the instrument.

With a little practice a weighing effected as above described takes but
a quarter or a fifth of the time that it does with an ordinary
balance.--_Revue Industrielle._

* * * * *

STARCHES FOR THE FINISHING OF COTTON FABRICS.

The starches have been classified by Dr. Muter, according to the
appearance they give under the microscope, into five groups:

_Class I_.--Hilum and concentric rings visible. All the granules, oval
or ovate. Tous-le-mois, potato, arrowroot, etc.

_Class II_.--The concentric rings are all but invisible, the hilum is
stellate. Maize, pea, bean, etc.

_Class III_.--The concentric rings are all but invisible, also the hilum
in the majority of granules. Wheat, barley, rye, chestnut, etc.

_Class IV_.--All the granules truncated at one end. Sago, tapioca, etc.

_Class V_.--All the granules angular in form. Rice, tacca, arrowroot,
oats, etc.

The principal starches used for finishing cotton fabrics are potato
(farina), wheat, Indian corn (maize), rice, tapioca, arrowroot, sago;
the last three not so often as those previously named.