19 | 71.46 | 13.13 | 10.40 | None | 0.120 | 44.8
3 | 1.29 | 69.42 | 24.72 | 4.17 | 1.12 | 0.280 | 5.22
4 | 8.40 | 60.98 | 10.98 | 10.09 | 9.02 | 0.530 | 20.0
5 | 10.60 | 44.98 | 8.05 | 12.20 | 23.57 | 0.600 | 52.0
6 | 14.80 | 11.57 | 36.46 | 34.87 | 1.89 | 0.580 | 8.0
7 | 8.00 | 29.61 | 26.78 | 33.98 | 0.88 | 0.750 | 88.0
8 | 2.29 | 52.38 | 37.65 | None | 7.335 | 0.315 | 9.6
----+---------+---------+--------+----------+-------+-------+---------

In those cases in which the substitute is made by admixture with gelatin
or liquid glue the quantity of other organic matter obtained can be
checked by a Kjeldahl determination of the total nitrogen. If a natural
gum is added, it will be partially converted into sugar when the
filtered liquid is inverted, and so make the dextrin determination
slightly too high.

* * * * *

MR. CAILLETET'S CRYOGEN.

The "cryogen," a new apparatus constructed by Mr. E. Ducretet, from
instructions given by Mr. Cailletet, is designed for effecting a fall of
temperature of from 70 deg. to 80 deg. C. below zero, through the expansion of
liquid carbonic acid.

The apparatus consists of two concentric vessels having an annular space
between them of a few centimeters. A worm, S, is placed in the internal
vessel R. All this is of nickel plated copper. The worm, S carries, at
Ro', an expansion cock and ends, at O in the annular space, R'. A very
strong tube is fixed to the cock, Ro', and to the ajutage, A'. It
receives the tube, Tu, which, at the time of an experiment, is coupled
with the cylinder of carbonic acid, CO squared. A tubulure, D, usually closed
by a plug, Bo, communicates with the inner receptacle, R. This is
capable of serving in certain experiments in condensation. The table,
Ta, of the tripod receives the various vessels or bottles for the
condensed products.

The entire apparatus is placed in a box, B, lined with silk waste and
provided with a cover, C, of the same structure. Apertures, Th, Ro, and
T", allow of the passage of a key for acting upon the cock, Ro', as well
as of thermometers and stirrers if they are necessary.

When it is desired to operate, the internal vessel, R, is filled with
alcohol (3 quarts for the ordinary model). This serves as a refrigerant
bath for the experiments to be made. The worm, S, having been put in
communication with the car