A modified aræometer has been recently patented by Aug. Eichhorn, in
Dresden, Germany (Deutsches Reichs-Patent, No. 49,683), which will
prove a great boon to chemists, distillers, physicians, etc., as it
affords an easy means of determining the specific gravity of liquids,
especially such of which only small quantities can be conveniently
obtained.
With the ordinary aræometers, as hitherto constructed, a considerable
quantity of the test fluid is required, and an elaborate calculation
necessary for each determination. In the new aræo-picnometer these
drawbacks are ingeniously avoided, so that the specific gravity of any
liquid can be quickly and easily obtained with astonishing accuracy.
The new and important feature of this instrument consists in a glass
bulb, c--see accompanying sketch--which is filled with the liquid
whose gravity is to be determined. Thus, instead of floating the
entire apparatus in the test fluid, only a very small quantity of the
latter is required, an advantage which can hardly be overestimated,
considering how difficult it is in many instances to procure the
necessary supply.
[Illustration]
^
=
=
=
= a
=
=
\ = /
| = |
|~~~~~~~~~~~~~~|
| - - = - -|
|- - = - |
| - - = - -|
|- - = - |
| - / \ -|
|- - | b | - |
| \ / -|
|- e//¯ ¯\\d |
| - | c | -|
|- \ _ / |
| - \ / -|
|- = - |
| - = -|
|- | | - |
| - \f/ -|
|- - v - |
| -|
/ \
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
The glass bulb, c, when filled with the test fluid, is closed by means
of an accurately fitting glass stopper, d, and the instrument is then
placed in a glass cylinder filled with distilled water of 17.5 deg.
temperature (Centigrade). The gravity is then at once shown on the
divided scale in the tube, a. The lower bulb, f, contains some
mercury; e is a small glass knob, which serves to maintain the
balance, while b is an empty glass bulb (floater).
These instruments are admirably adapted for determining the gravity of
alcohol, petroleum, benzine, and every kind of oil, also for testing
beer, milk, vinegar, grape juice, lye, glycerine, urine, etc.
As the process is an exceedingly simple one and free from the
drawbacks of the aræometer, we are justified in concluding that the
aræo-picnometer will soon be in general use.
H. HENSOLDT, Ph.D.
Petrographical Laboratory, School of Mines, Columbia College.
* * * * *
[Continued from SUPPLEMENT, No. 793, page 12669.]